New upstream version 4.8

21 files changed, 1020 insertions, 806 deletions

diff --git a/build-aux/announce-gen b/build-aux/announce-gen
index eeb9071..aebb86f 100755
--- a/build-aux/announce-gen
+++ b/build-aux/announce-gen
@@ -1,33 +1,47 @@
-eval '(exit $?0)' && eval 'exec perl -wS "$0" "$@"'
-  & eval 'exec perl -wS "$0" $argv:q'
-    if 0;
-# Generate a release announcement message.
-
-my $VERSION = '2018-03-07 03:46'; # UTC
-# The definition above must lie within the first 8 lines in order
-# for the Emacs time-stamp write hook (at end) to update it.
-# If you change this file with Emacs, please let the write hook
-# do its job.  Otherwise, update this string manually.
+#!/bin/sh
+#! -*-perl-*-
 
-# Copyright (C) 2002-2018 Free Software Foundation, Inc.
+# Generate a release announcement message.
 
+# Copyright (C) 2002-2020 Free Software Foundation, Inc.
+#
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
-
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
-
+#
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
+#
 # Written by Jim Meyering
 
-use strict;
+# This is a prologue that allows to run a perl script as an executable
+# on systems that are compliant to a POSIX version before POSIX:2017.
+# On such systems, the usual invocation of an executable through execlp()
+# or execvp() fails with ENOEXEC if it is a script that does not start
+# with a #! line.  The script interpreter mentioned in the #! line has
+# to be /bin/sh, because on GuixSD systems that is the only program that
+# has a fixed file name.  The second line is essential for perl and is
+# also useful for editing this file in Emacs.  The next two lines below
+# are valid code in both sh and perl.  When executed by sh, they re-execute
+# the script through the perl program found in $PATH.  The '-x' option
+# is essential as well; without it, perl would re-execute the script
+# through /bin/sh.  When executed by  perl, the next two lines are a no-op.
+eval 'exec perl -wSx "$0" "$@"'
+     if 0;
 
+my $VERSION = '2018-03-07 03:46'; # UTC
+# The definition above must lie within the first 8 lines in order
+# for the Emacs time-stamp write hook (at end) to update it.
+# If you change this file with Emacs, please let the write hook
+# do its job.  Otherwise, update this string manually.
+
+use strict;
 use Getopt::Long;
 use POSIX qw(strftime);
 
@@ -550,6 +564,7 @@ EOF
 ## perl-extra-newline-before-brace: t
 ## perl-merge-trailing-else: nil
 ## eval: (add-hook 'before-save-hook 'time-stamp)
+## time-stamp-line-limit: 50
 ## time-stamp-start: "my $VERSION = '"
 ## time-stamp-format: "%:y-%02m-%02d %02H:%02M"
 ## time-stamp-time-zone: "UTC0"
diff --git a/build-aux/config.guess b/build-aux/config.guess
index 94c4ac1..45001cf 100755
--- a/build-aux/config.guess
+++ b/build-aux/config.guess
@@ -1,8 +1,8 @@
 #! /bin/sh
 # Attempt to guess a canonical system name.
-#   Copyright 1992-2018 Free Software Foundation, Inc.
+#   Copyright 1992-2020 Free Software Foundation, Inc.
 
-timestamp='2018-12-07'
+timestamp='2020-01-01'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -50,7 +50,7 @@ version="\
 GNU config.guess ($timestamp)
 
 Originally written by Per Bothner.
-Copyright 1992-2018 Free Software Foundation, Inc.
+Copyright 1992-2020 Free Software Foundation, Inc.
 
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@@ -99,6 +99,8 @@ tmp=
 trap 'test -z "$tmp" || rm -fr "$tmp"' 0 1 2 13 15
 
 set_cc_for_build() {
+    # prevent multiple calls if $tmp is already set
+    test "$tmp" && return 0
     : "${TMPDIR=/tmp}"
     # shellcheck disable=SC2039
     { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n "$tmp" && test -d "$tmp" ; } ||
@@ -262,6 +264,9 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
     *:SolidBSD:*:*)
 	echo "$UNAME_MACHINE"-unknown-solidbsd"$UNAME_RELEASE"
 	exit ;;
+    *:OS108:*:*)
+	echo "$UNAME_MACHINE"-unknown-os108_"$UNAME_RELEASE"
+	exit ;;
     macppc:MirBSD:*:*)
 	echo powerpc-unknown-mirbsd"$UNAME_RELEASE"
 	exit ;;
@@ -271,12 +276,15 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
     *:Sortix:*:*)
 	echo "$UNAME_MACHINE"-unknown-sortix
 	exit ;;
+    *:Twizzler:*:*)
+	echo "$UNAME_MACHINE"-unknown-twizzler
+	exit ;;
     *:Redox:*:*)
 	echo "$UNAME_MACHINE"-unknown-redox
 	exit ;;
     mips:OSF1:*.*)
-        echo mips-dec-osf1
-        exit ;;
+	echo mips-dec-osf1
+	exit ;;
     alpha:OSF1:*:*)
 	case $UNAME_RELEASE in
 	*4.0)
@@ -391,15 +399,20 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	echo i386-pc-auroraux"$UNAME_RELEASE"
 	exit ;;
     i86pc:SunOS:5.*:* | i86xen:SunOS:5.*:*)
-	UNAME_REL="`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`"
-	case `isainfo -b` in
-	    32)
-		echo i386-pc-solaris2"$UNAME_REL"
-		;;
-	    64)
-		echo x86_64-pc-solaris2"$UNAME_REL"
-		;;
-	esac
+	set_cc_for_build
+	SUN_ARCH=i386
+	# If there is a compiler, see if it is configured for 64-bit objects.
+	# Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
+	# This test works for both compilers.
+	if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+	    if (echo '#ifdef __amd64'; echo IS_64BIT_ARCH; echo '#endif') | \
+		(CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		grep IS_64BIT_ARCH >/dev/null
+	    then
+		SUN_ARCH=x86_64
+	    fi
+	fi
+	echo "$SUN_ARCH"-pc-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
 	exit ;;
     sun4*:SunOS:6*:*)
 	# According to config.sub, this is the proper way to canonicalize
@@ -913,7 +926,7 @@ EOF
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
 	exit ;;
     alpha:Linux:*:*)
-	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo` in
+	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' /proc/cpuinfo 2>/dev/null` in
 	  EV5)   UNAME_MACHINE=alphaev5 ;;
 	  EV56)  UNAME_MACHINE=alphaev56 ;;
 	  PCA56) UNAME_MACHINE=alphapca56 ;;
@@ -980,22 +993,50 @@ EOF
 	exit ;;
     mips:Linux:*:* | mips64:Linux:*:*)
 	set_cc_for_build
+	IS_GLIBC=0
+	test x"${LIBC}" = xgnu && IS_GLIBC=1
 	sed 's/^	//' << EOF > "$dummy.c"
 	#undef CPU
-	#undef ${UNAME_MACHINE}
-	#undef ${UNAME_MACHINE}el
+	#undef mips
+	#undef mipsel
+	#undef mips64
+	#undef mips64el
+	#if ${IS_GLIBC} && defined(_ABI64)
+	LIBCABI=gnuabi64
+	#else
+	#if ${IS_GLIBC} && defined(_ABIN32)
+	LIBCABI=gnuabin32
+	#else
+	LIBCABI=${LIBC}
+	#endif
+	#endif
+
+	#if ${IS_GLIBC} && defined(__mips64) && defined(__mips_isa_rev) && __mips_isa_rev>=6
+	CPU=mipsisa64r6
+	#else
+	#if ${IS_GLIBC} && !defined(__mips64) && defined(__mips_isa_rev) && __mips_isa_rev>=6
+	CPU=mipsisa32r6
+	#else
+	#if defined(__mips64)
+	CPU=mips64
+	#else
+	CPU=mips
+	#endif
+	#endif
+	#endif
+
 	#if defined(__MIPSEL__) || defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL)
-	CPU=${UNAME_MACHINE}el
+	MIPS_ENDIAN=el
 	#else
 	#if defined(__MIPSEB__) || defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB)
-	CPU=${UNAME_MACHINE}
+	MIPS_ENDIAN=
 	#else
-	CPU=
+	MIPS_ENDIAN=
 	#endif
 	#endif
 EOF
-	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^CPU'`"
-	test "x$CPU" != x && { echo "$CPU-unknown-linux-$LIBC"; exit; }
+	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^CPU\|^MIPS_ENDIAN\|^LIBCABI'`"
+	test "x$CPU" != x && { echo "$CPU${MIPS_ENDIAN}-unknown-linux-$LIBCABI"; exit; }
 	;;
     mips64el:Linux:*:*)
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
@@ -1108,7 +1149,7 @@ EOF
 	    *Pentium)	     UNAME_MACHINE=i586 ;;
 	    *Pent*|*Celeron) UNAME_MACHINE=i686 ;;
 	esac
-	echo "$UNAME_MACHINE-unknown-sysv${UNAME_RELEASE}${UNAME_SYSTEM}{$UNAME_VERSION}"
+	echo "$UNAME_MACHINE-unknown-sysv${UNAME_RELEASE}${UNAME_SYSTEM}${UNAME_VERSION}"
 	exit ;;
     i*86:*:3.2:*)
 	if test -f /usr/options/cb.name; then
@@ -1292,38 +1333,39 @@ EOF
 	echo "$UNAME_MACHINE"-apple-rhapsody"$UNAME_RELEASE"
 	exit ;;
     *:Darwin:*:*)
-	UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
-	set_cc_for_build
-	if test "$UNAME_PROCESSOR" = unknown ; then
-	    UNAME_PROCESSOR=powerpc
+	UNAME_PROCESSOR=`uname -p`
+	case $UNAME_PROCESSOR in
+	    unknown) UNAME_PROCESSOR=powerpc ;;
+	esac
+	if command -v xcode-select > /dev/null 2> /dev/null && \
+		! xcode-select --print-path > /dev/null 2> /dev/null ; then
+	    # Avoid executing cc if there is no toolchain installed as
+	    # cc will be a stub that puts up a graphical alert
+	    # prompting the user to install developer tools.
+	    CC_FOR_BUILD=no_compiler_found
+	else
+	    set_cc_for_build
 	fi
-	if test "`echo "$UNAME_RELEASE" | sed -e 's/\..*//'`" -le 10 ; then
-	    if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
-		if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
-		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
-		       grep IS_64BIT_ARCH >/dev/null
-		then
-		    case $UNAME_PROCESSOR in
-			i386) UNAME_PROCESSOR=x86_64 ;;
-			powerpc) UNAME_PROCESSOR=powerpc64 ;;
-		    esac
-		fi
-		# On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
-		if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
-		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
-		       grep IS_PPC >/dev/null
-		then
-		    UNAME_PROCESSOR=powerpc
-		fi
+	if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+	    if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
+		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		   grep IS_64BIT_ARCH >/dev/null
+	    then
+		case $UNAME_PROCESSOR in
+		    i386) UNAME_PROCESSOR=x86_64 ;;
+		    powerpc) UNAME_PROCESSOR=powerpc64 ;;
+		esac
+	    fi
+	    # On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
+	    if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
+		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		   grep IS_PPC >/dev/null
+	    then
+		UNAME_PROCESSOR=powerpc
 	    fi
 	elif test "$UNAME_PROCESSOR" = i386 ; then
-	    # Avoid executing cc on OS X 10.9, as it ships with a stub
-	    # that puts up a graphical alert prompting to install
-	    # developer tools.  Any system running Mac OS X 10.7 or
-	    # later (Darwin 11 and later) is required to have a 64-bit
-	    # processor. This is not true of the ARM version of Darwin
-	    # that Apple uses in portable devices.
-	    UNAME_PROCESSOR=x86_64
+	    # uname -m returns i386 or x86_64
+	    UNAME_PROCESSOR=$UNAME_MACHINE
 	fi
 	echo "$UNAME_PROCESSOR"-apple-darwin"$UNAME_RELEASE"
 	exit ;;
@@ -1428,6 +1470,143 @@ EOF
 	exit ;;
 esac
 
+# No uname command or uname output not recognized.
+set_cc_for_build
+cat > "$dummy.c" <<EOF
+#ifdef _SEQUENT_
+#include <sys/types.h>
+#include <sys/utsname.h>
+#endif
+#if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || defined(__ultrix__)
+#if defined (vax) || defined (__vax) || defined (__vax__) || defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
+#include <signal.h>
+#if defined(_SIZE_T_) || defined(SIGLOST)
+#include <sys/utsname.h>
+#endif
+#endif
+#endif
+main ()
+{
+#if defined (sony)
+#if defined (MIPSEB)
+  /* BFD wants "bsd" instead of "newsos".  Perhaps BFD should be changed,
+     I don't know....  */
+  printf ("mips-sony-bsd\n"); exit (0);
+#else
+#include <sys/param.h>
+  printf ("m68k-sony-newsos%s\n",
+#ifdef NEWSOS4
+  "4"
+#else
+  ""
+#endif
+  ); exit (0);
+#endif
+#endif
+
+#if defined (NeXT)
+#if !defined (__ARCHITECTURE__)
+#define __ARCHITECTURE__ "m68k"
+#endif
+  int version;
+  version=`(hostinfo | sed -n 's/.*NeXT Mach \([0-9]*\).*/\1/p') 2>/dev/null`;
+  if (version < 4)
+    printf ("%s-next-nextstep%d\n", __ARCHITECTURE__, version);
+  else
+    printf ("%s-next-openstep%d\n", __ARCHITECTURE__, version);
+  exit (0);
+#endif
+
+#if defined (MULTIMAX) || defined (n16)
+#if defined (UMAXV)
+  printf ("ns32k-encore-sysv\n"); exit (0);
+#else
+#if defined (CMU)
+  printf ("ns32k-encore-mach\n"); exit (0);
+#else
+  printf ("ns32k-encore-bsd\n"); exit (0);
+#endif
+#endif
+#endif
+
+#if defined (__386BSD__)
+  printf ("i386-pc-bsd\n"); exit (0);
+#endif
+
+#if defined (sequent)
+#if defined (i386)
+  printf ("i386-sequent-dynix\n"); exit (0);
+#endif
+#if defined (ns32000)
+  printf ("ns32k-sequent-dynix\n"); exit (0);
+#endif
+#endif
+
+#if defined (_SEQUENT_)
+  struct utsname un;
+
+  uname(&un);
+  if (strncmp(un.version, "V2", 2) == 0) {
+    printf ("i386-sequent-ptx2\n"); exit (0);
+  }
+  if (strncmp(un.version, "V1", 2) == 0) { /* XXX is V1 correct? */
+    printf ("i386-sequent-ptx1\n"); exit (0);
+  }
+  printf ("i386-sequent-ptx\n"); exit (0);
+#endif
+
+#if defined (vax)
+#if !defined (ultrix)
+#include <sys/param.h>
+#if defined (BSD)
+#if BSD == 43
+  printf ("vax-dec-bsd4.3\n"); exit (0);
+#else
+#if BSD == 199006
+  printf ("vax-dec-bsd4.3reno\n"); exit (0);
+#else
+  printf ("vax-dec-bsd\n"); exit (0);
+#endif
+#endif
+#else
+  printf ("vax-dec-bsd\n"); exit (0);
+#endif
+#else
+#if defined(_SIZE_T_) || defined(SIGLOST)
+  struct utsname un;
+  uname (&un);
+  printf ("vax-dec-ultrix%s\n", un.release); exit (0);
+#else
+  printf ("vax-dec-ultrix\n"); exit (0);
+#endif
+#endif
+#endif
+#if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || defined(__ultrix__)
+#if defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
+#if defined(_SIZE_T_) || defined(SIGLOST)
+  struct utsname *un;
+  uname (&un);
+  printf ("mips-dec-ultrix%s\n", un.release); exit (0);
+#else
+  printf ("mips-dec-ultrix\n"); exit (0);
+#endif
+#endif
+#endif
+
+#if defined (alliant) && defined (i860)
+  printf ("i860-alliant-bsd\n"); exit (0);
+#endif
+
+  exit (1);
+}
+EOF
+
+$CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null && SYSTEM_NAME=`$dummy` &&
+	{ echo "$SYSTEM_NAME"; exit; }
+
+# Apollos put the system type in the environment.
+test -d /usr/apollo && { echo "$ISP-apollo-$SYSTYPE"; exit; }
+
 echo "$0: unable to guess system type" >&2
 
 case "$UNAME_MACHINE:$UNAME_SYSTEM" in
diff --git a/build-aux/config.rpath b/build-aux/config.rpath
index fc5913d..b625621 100755
--- a/build-aux/config.rpath
+++ b/build-aux/config.rpath
@@ -2,7 +2,7 @@
 # Output a system dependent set of variables, describing how to set the
 # run time search path of shared libraries in an executable.
 #
-#   Copyright 1996-2018 Free Software Foundation, Inc.
+#   Copyright 1996-2014 Free Software Foundation, Inc.
 #   Taken from GNU libtool, 2001
 #   Originally by Gordon Matzigkeit <gord@gnu.ai.mit.edu>, 1996
 #
diff --git a/build-aux/config.sub b/build-aux/config.sub
index a5081b8..f02d43a 100755
--- a/build-aux/config.sub
+++ b/build-aux/config.sub
@@ -1,8 +1,8 @@
 #! /bin/sh
 # Configuration validation subroutine script.
-#   Copyright 1992-2018 Free Software Foundation, Inc.
+#   Copyright 1992-2020 Free Software Foundation, Inc.
 
-timestamp='2018-12-16'
+timestamp='2020-01-01'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -67,7 +67,7 @@ Report bugs and patches to <config-patches@gnu.org>."
 version="\
 GNU config.sub ($timestamp)
 
-Copyright 1992-2018 Free Software Foundation, Inc.
+Copyright 1992-2020 Free Software Foundation, Inc.
 
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@@ -111,6 +111,7 @@ case $# in
 esac
 
 # Split fields of configuration type
+# shellcheck disable=SC2162
 IFS="-" read field1 field2 field3 field4 <<EOF
 $1
 EOF
@@ -336,17 +337,14 @@ case $1 in
 				basic_machine=m88k-harris
 				os=sysv3
 				;;
-			hp300)
+			hp300 | hp300hpux)
 				basic_machine=m68k-hp
+				os=hpux
 				;;
 			hp300bsd)
 				basic_machine=m68k-hp
 				os=bsd
 				;;
-			hp300hpux)
-				basic_machine=m68k-hp
-				os=hpux
-				;;
 			hppaosf)
 				basic_machine=hppa1.1-hp
 				os=osf
@@ -359,10 +357,6 @@ case $1 in
 				basic_machine=i386-mach
 				os=mach
 				;;
-			vsta)
-				basic_machine=i386-pc
-				os=vsta
-				;;
 			isi68 | isi)
 				basic_machine=m68k-isi
 				os=sysv
@@ -611,6 +605,10 @@ case $1 in
 				basic_machine=vax-dec
 				os=vms
 				;;
+			vsta)
+				basic_machine=i386-pc
+				os=vsta
+				;;
 			vxworks960)
 				basic_machine=i960-wrs
 				os=vxworks
@@ -821,7 +819,9 @@ case $basic_machine in
 		cpu=m68k
 		vendor=next
 		case $os in
-		    nextstep* )
+		    openstep*)
+		        ;;
+		    nextstep*)
 			;;
 		    ns2*)
 		      os=nextstep2
@@ -918,6 +918,7 @@ case $basic_machine in
 		;;
 
 	*-*)
+		# shellcheck disable=SC2162
 		IFS="-" read cpu vendor <<EOF
 $basic_machine
 EOF
@@ -1168,7 +1169,7 @@ case $cpu-$vendor in
 			| asmjs \
 			| ba \
 			| be32 | be64 \
-			| bfin | bs2000 \
+			| bfin | bpf | bs2000 \
 			| c[123]* | c30 | [cjt]90 | c4x \
 			| c8051 | clipper | craynv | csky | cydra \
 			| d10v | d30v | dlx | dsp16xx \
@@ -1183,13 +1184,13 @@ case $cpu-$vendor in
 			| le32 | le64 \
 			| lm32 \
 			| m32c | m32r | m32rle \
-			| m5200 | m68000 | m680[012346]0 | m68360 | m683?2 | m68k | v70 | w65 \
-			| m6811 | m68hc11 | m6812 | m68hc12 | m68hcs12x | nvptx | picochip \
+			| m5200 | m68000 | m680[012346]0 | m68360 | m683?2 | m68k \
+			| m6811 | m68hc11 | m6812 | m68hc12 | m68hcs12x \
 			| m88110 | m88k | maxq | mb | mcore | mep | metag \
 			| microblaze | microblazeel \
 			| mips | mipsbe | mipseb | mipsel | mipsle \
 			| mips16 \
-			| mips64 | mips64el \
+			| mips64 | mips64eb | mips64el \
 			| mips64octeon | mips64octeonel \
 			| mips64orion | mips64orionel \
 			| mips64r5900 | mips64r5900el \
@@ -1216,11 +1217,12 @@ case $cpu-$vendor in
 			| nds32 | nds32le | nds32be \
 			| nfp \
 			| nios | nios2 | nios2eb | nios2el \
-			| none | np1 | ns16k | ns32k \
+			| none | np1 | ns16k | ns32k | nvptx \
 			| open8 \
 			| or1k* \
 			| or32 \
 			| orion \
+			| picochip \
 			| pdp10 | pdp11 | pj | pjl | pn | power \
 			| powerpc | powerpc64 | powerpc64le | powerpcle | powerpcspe \
 			| pru \
@@ -1228,7 +1230,8 @@ case $cpu-$vendor in
 			| riscv | riscv32 | riscv64 \
 			| rl78 | romp | rs6000 | rx \
 			| score \
-			| sh | sh[1234] | sh[24]a | sh[24]ae[lb] | sh[23]e | she[lb] | sh[lb]e \
+			| sh | shl \
+			| sh[1234] | sh[24]a | sh[24]ae[lb] | sh[23]e | she[lb] | sh[lb]e \
 			| sh[1234]e[lb] |  sh[12345][lb]e | sh[23]ele | sh64 | sh64le \
 			| sparc | sparc64 | sparc64b | sparc64v | sparc86x | sparclet \
 			| sparclite \
@@ -1238,10 +1241,11 @@ case $cpu-$vendor in
 			| tic30 | tic4x | tic54x | tic55x | tic6x | tic80 \
 			| tron \
 			| ubicom32 \
-			| v850 | v850e | v850e1 | v850es | v850e2 | v850e2v3 \
+			| v70 | v850 | v850e | v850e1 | v850es | v850e2 | v850e2v3 \
 			| vax \
 			| visium \
-			| wasm32 \
+			| w65 \
+			| wasm32 | wasm64 \
 			| we32k \
 			| x86 | x86_64 | xc16x | xgate | xps100 \
 			| xstormy16 | xtensa* \
@@ -1339,11 +1343,11 @@ case $os in
 	     | hpux* | unos* | osf* | luna* | dgux* | auroraux* | solaris* \
 	     | sym* | kopensolaris* | plan9* \
 	     | amigaos* | amigados* | msdos* | newsos* | unicos* | aof* \
-	     | aos* | aros* | cloudabi* | sortix* \
+	     | aos* | aros* | cloudabi* | sortix* | twizzler* \
 	     | nindy* | vxsim* | vxworks* | ebmon* | hms* | mvs* \
 	     | clix* | riscos* | uniplus* | iris* | isc* | rtu* | xenix* \
 	     | knetbsd* | mirbsd* | netbsd* \
-	     | bitrig* | openbsd* | solidbsd* | libertybsd* \
+	     | bitrig* | openbsd* | solidbsd* | libertybsd* | os108* \
 	     | ekkobsd* | kfreebsd* | freebsd* | riscix* | lynxos* \
 	     | bosx* | nextstep* | cxux* | aout* | elf* | oabi* \
 	     | ptx* | coff* | ecoff* | winnt* | domain* | vsta* \
@@ -1361,7 +1365,8 @@ case $os in
 	     | powermax* | dnix* | nx6 | nx7 | sei* | dragonfly* \
 	     | skyos* | haiku* | rdos* | toppers* | drops* | es* \
 	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
-	     | midnightbsd* | amdhsa* | unleashed*)
+	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
+	     | nsk* | powerunix)
 	# Remember, each alternative MUST END IN *, to match a version number.
 		;;
 	qnx*)
@@ -1445,9 +1450,6 @@ case $os in
 	ns2)
 		os=nextstep2
 		;;
-	nsk*)
-		os=nsk
-		;;
 	# Preserve the version number of sinix5.
 	sinix5.*)
 		os=`echo $os | sed -e 's|sinix|sysv|'`
diff --git a/build-aux/depcomp b/build-aux/depcomp
index 65cbf70..6b39162 100755
--- a/build-aux/depcomp
+++ b/build-aux/depcomp
@@ -3,7 +3,7 @@
 
 scriptversion=2018-03-07.03; # UTC
 
-# Copyright (C) 1999-2018 Free Software Foundation, Inc.
+# Copyright (C) 1999-2020 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/do-release-commit-and-tag b/build-aux/do-release-commit-and-tag
index 4472ff5..f4ec1b1 100755
--- a/build-aux/do-release-commit-and-tag
+++ b/build-aux/do-release-commit-and-tag
@@ -7,7 +7,7 @@ VERSION=2018-03-07.03 # UTC
 
 # Note: this is a bash script (could be zsh or dash)
 
-# Copyright (C) 2009-2018 Free Software Foundation, Inc.
+# Copyright (C) 2009-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/gendocs.sh b/build-aux/gendocs.sh
index 91c058d..dec8eb9 100755
--- a/build-aux/gendocs.sh
+++ b/build-aux/gendocs.sh
@@ -2,9 +2,9 @@
 # gendocs.sh -- generate a GNU manual in many formats.  This script is
 #   mentioned in maintain.texi.  See the help message below for usage details.
 
-scriptversion=2018-03-06.19
+scriptversion=2020-01-01.00
 
-# Copyright 2003-2018 Free Software Foundation, Inc.
+# Copyright 2003-2020 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -73,7 +73,7 @@ texarg="-t @finalout"
 
 version="gendocs.sh $scriptversion
 
-Copyright 2018 Free Software Foundation, Inc.
+Copyright 2020 Free Software Foundation, Inc.
 There is NO warranty.  You may redistribute this software
 under the terms of the GNU General Public License.
 For more information about these matters, see the files named COPYING."
diff --git a/build-aux/git-version-gen b/build-aux/git-version-gen
index 6d073fc..d90b0ef 100755
--- a/build-aux/git-version-gen
+++ b/build-aux/git-version-gen
@@ -2,7 +2,7 @@
 # Print a version string.
 scriptversion=2018-03-07.03; # UTC
 
-# Copyright (C) 2007-2018 Free Software Foundation, Inc.
+# Copyright (C) 2007-2020 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -72,9 +72,10 @@ scriptversion=2018-03-07.03; # UTC
 
 me=$0
 
+year=`expr "$scriptversion" : '\([^-]*\)'`
 version="git-version-gen $scriptversion
 
-Copyright 2011 Free Software Foundation, Inc.
+Copyright $year Free Software Foundation, Inc.
 There is NO warranty.  You may redistribute this software
 under the terms of the GNU General Public License.
 For more information about these matters, see the files named COPYING."
@@ -141,11 +142,9 @@ then
     v=`cat $tarball_version_file` || v=
     case $v in
         *$nl*) v= ;; # reject multi-line output
-        [0-9]*) ;;
-        *) v= ;;
     esac
     test "x$v" = x \
-        && echo "$0: WARNING: $tarball_version_file is missing or damaged" 1>&2
+        && echo "$0: WARNING: $tarball_version_file is damaged" 1>&2
 fi
 
 if test "x$v" != x
diff --git a/build-aux/gitlog-to-changelog b/build-aux/gitlog-to-changelog
index 1e73f42..5112767 100755
--- a/build-aux/gitlog-to-changelog
+++ b/build-aux/gitlog-to-changelog
@@ -1,31 +1,46 @@
-eval '(exit $?0)' && eval 'exec perl -wS "$0" "$@"'
-  & eval 'exec perl -wS "$0" $argv:q'
-    if 0;
-# Convert git log output to ChangeLog format.
+#!/bin/sh
+#! -*-perl-*-
 
-my $VERSION = '2018-03-07 03:47'; # UTC
-# The definition above must lie within the first 8 lines in order
-# for the Emacs time-stamp write hook (at end) to update it.
-# If you change this file with Emacs, please let the write hook
-# do its job.  Otherwise, update this string manually.
-
-# Copyright (C) 2008-2018 Free Software Foundation, Inc.
+# Convert git log output to ChangeLog format.
 
+# Copyright (C) 2008-2020 Free Software Foundation, Inc.
+#
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
-
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
-
+#
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
+#
 # Written by Jim Meyering
 
+# This is a prologue that allows to run a perl script as an executable
+# on systems that are compliant to a POSIX version before POSIX:2017.
+# On such systems, the usual invocation of an executable through execlp()
+# or execvp() fails with ENOEXEC if it is a script that does not start
+# with a #! line.  The script interpreter mentioned in the #! line has
+# to be /bin/sh, because on GuixSD systems that is the only program that
+# has a fixed file name.  The second line is essential for perl and is
+# also useful for editing this file in Emacs.  The next two lines below
+# are valid code in both sh and perl.  When executed by sh, they re-execute
+# the script through the perl program found in $PATH.  The '-x' option
+# is essential as well; without it, perl would re-execute the script
+# through /bin/sh.  When executed by  perl, the next two lines are a no-op.
+eval 'exec perl -wSx "$0" "$@"'
+     if 0;
+
+my $VERSION = '2018-03-07 03:47'; # UTC
+# The definition above must lie within the first 8 lines in order
+# for the Emacs time-stamp write hook (at end) to update it.
+# If you change this file with Emacs, please let the write hook
+# do its job.  Otherwise, update this string manually.
+
 use strict;
 use warnings;
 use Getopt::Long;
@@ -174,7 +189,7 @@ sub parse_amend_file($)
 
       if (!$in_code)
         {
-          $line =~ /^([0-9a-fA-F]{40})$/
+          $line =~ /^([[:xdigit:]]{40})$/
             or (warn "$ME: $f:$.: invalid line; expected an SHA1\n"),
               $fail = 1, next;
           $sha = lc $1;
@@ -288,7 +303,7 @@ sub git_dir_option($)
       my ($sha, $rest) = split ':', $log, 2;
       defined $sha
         or die "$ME:$.: malformed log entry\n";
-      $sha =~ /^[0-9a-fA-F]{40}$/
+      $sha =~ /^[[:xdigit:]]{40}$/
         or die "$ME:$.: invalid SHA1: $sha\n";
 
       my $skipflag = 0;
@@ -376,7 +391,7 @@ sub git_dir_option($)
                   @skipshas = ();
                   next;
               }
-              if ($found && $_ =~ /^([0-9a-fA-F]{7,}) [^ ]/)
+              if ($found && $_ =~ /^([[:xdigit:]]{7,}) [^ ]/)
               {
                   push ( @skipshas, $1 );
               }
@@ -492,6 +507,7 @@ sub git_dir_option($)
 # mode: perl
 # indent-tabs-mode: nil
 # eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-line-limit: 50
 # time-stamp-start: "my $VERSION = '"
 # time-stamp-format: "%:y-%02m-%02d %02H:%02M"
 # time-stamp-time-zone: "UTC0"
diff --git a/build-aux/gnu-web-doc-update b/build-aux/gnu-web-doc-update
index 356c561..ff48cf7 100755
--- a/build-aux/gnu-web-doc-update
+++ b/build-aux/gnu-web-doc-update
@@ -4,7 +4,7 @@
 
 VERSION=2018-03-07.03; # UTC
 
-# Copyright (C) 2009-2018 Free Software Foundation, Inc.
+# Copyright (C) 2009-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/gnupload b/build-aux/gnupload
index 8f05700..e4ea542 100755
--- a/build-aux/gnupload
+++ b/build-aux/gnupload
@@ -3,7 +3,7 @@
 
 scriptversion=2018-05-19.18; # UTC
 
-# Copyright (C) 2004-2018 Free Software Foundation, Inc.
+# Copyright (C) 2004-2020 Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -116,12 +116,22 @@ Examples:
            --symlink-regex \\
            foobar-1.0.tar.gz foobar-1.0.tar.xz
 
-4. Upload foobar-0.9.90.tar.gz to two sites:
+4. Create a symbolic link foobar-latest.tar.gz -> foobar-1.0.tar.gz
+   and likewise for the corresponding .sig file:
+  gnupload --to ftp.gnu.org:foobar \\
+           --symlink foobar-1.0.tar.gz     foobar-latest.tar.gz \\
+                     foobar-1.0.tar.gz.sig foobar-latest.tar.gz.sig
+  or (equivalent):
+  gnupload --to ftp.gnu.org:foobar \\
+           --symlink foobar-1.0.tar.gz     foobar-latest.tar.gz \\
+           --symlink foobar-1.0.tar.gz.sig foobar-latest.tar.gz.sig
+
+5. Upload foobar-0.9.90.tar.gz to two sites:
   gnupload --to alpha.gnu.org:foobar \\
            --to sources.redhat.com:~ftp/pub/foobar \\
            foobar-0.9.90.tar.gz
 
-5. Delete oopsbar-0.9.91.tar.gz and upload foobar-0.9.91.tar.gz
+6. Delete oopsbar-0.9.91.tar.gz and upload foobar-0.9.91.tar.gz
    (the -- terminates the list of files to delete):
   gnupload --to alpha.gnu.org:foobar \\
            --to sources.redhat.com:~ftp/pub/foobar \\
diff --git a/build-aux/help2man b/build-aux/help2man
index c9f904b..b50dced 100755
--- a/build-aux/help2man
+++ b/build-aux/help2man
@@ -1,7 +1,7 @@
 #!/usr/bin/env perl
 
 # Generate a short man page from --help and --version output.
-# Copyright (C) 1997-2018 Free Software Foundation, Inc.
+# Copyright (C) 1997-2020 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/install-sh b/build-aux/install-sh
index 8175c64..20d8b2e 100755
--- a/build-aux/install-sh
+++ b/build-aux/install-sh
@@ -451,7 +451,18 @@ do
     trap 'ret=$?; rm -f "$dsttmp" "$rmtmp" && exit $ret' 0
 
     # Copy the file name to the temp name.
-    (umask $cp_umask && $doit_exec $cpprog "$src" "$dsttmp") &&
+    (umask $cp_umask &&
+     { test -z "$stripcmd" || {
+	 # Create $dsttmp read-write so that cp doesn't create it read-only,
+	 # which would cause strip to fail.
+	 if test -z "$doit"; then
+	   : >"$dsttmp" # No need to fork-exec 'touch'.
+	 else
+	   $doit touch "$dsttmp"
+	 fi
+       }
+     } &&
+     $doit_exec $cpprog "$src" "$dsttmp") &&
 
     # and set any options; do chmod last to preserve setuid bits.
     #
diff --git a/build-aux/mdate-sh b/build-aux/mdate-sh
index 8c7a590..6a6a4bc 100755
--- a/build-aux/mdate-sh
+++ b/build-aux/mdate-sh
@@ -3,7 +3,7 @@
 
 scriptversion=2018-03-07.03; # UTC
 
-# Copyright (C) 1995-2018 Free Software Foundation, Inc.
+# Copyright (C) 1995-2020 Free Software Foundation, Inc.
 # written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, June 1995
 #
 # This program is free software; you can redistribute it and/or modify
diff --git a/build-aux/missing b/build-aux/missing
index 625aeb1..8d0eaad 100755
--- a/build-aux/missing
+++ b/build-aux/missing
@@ -3,7 +3,7 @@
 
 scriptversion=2018-03-07.03; # UTC
 
-# Copyright (C) 1996-2018 Free Software Foundation, Inc.
+# Copyright (C) 1996-2020 Free Software Foundation, Inc.
 # Originally written by Fran,cois Pinard <pinard@iro.umontreal.ca>, 1996.
 
 # This program is free software; you can redistribute it and/or modify
diff --git a/build-aux/prefix-gnulib-mk b/build-aux/prefix-gnulib-mk
index 544654f..674615a 100755
--- a/build-aux/prefix-gnulib-mk
+++ b/build-aux/prefix-gnulib-mk
@@ -1,13 +1,51 @@
-eval '(exit $?0)' && eval 'exec perl -wS "$0" "$@"'
-  & eval 'exec perl -wS "$0" $argv:q'
-    if 0;
+#!/bin/sh
+#! -*-perl-*-
+
+# Rewrite a gnulib.mk, adding prefixes to work with automake's subdir-objects.
+
+# Copyright (C) 2012-2020 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+# Written by Jim Meyering
+
+# This is a prologue that allows to run a perl script as an executable
+# on systems that are compliant to a POSIX version before POSIX:2017.
+# On such systems, the usual invocation of an executable through execlp()
+# or execvp() fails with ENOEXEC if it is a script that does not start
+# with a #! line.  The script interpreter mentioned in the #! line has
+# to be /bin/sh, because on GuixSD systems that is the only program that
+# has a fixed file name.  The second line is essential for perl and is
+# also useful for editing this file in Emacs.  The next two lines below
+# are valid code in both sh and perl.  When executed by sh, they re-execute
+# the script through the perl program found in $PATH.  The '-x' option
+# is essential as well; without it, perl would re-execute the script
+# through /bin/sh.  When executed by  perl, the next two lines are a no-op.
+eval 'exec perl -wSx "$0" "$@"'
+     if 0;
+
+my $VERSION = '2012-01-21 17:13'; # UTC
+# The definition above must lie within the first 8 lines in order
+# for the Emacs time-stamp write hook (at end) to update it.
+# If you change this file with Emacs, please let the write hook
+# do its job.  Otherwise, update this string manually.
 
 use strict;
 use IO::File;
 use Getopt::Long;
 use File::Basename; # for dirname
 
-my $VERSION = '2012-01-21 17:13'; # UTC
 (my $ME = $0) =~ s|.*/||;
 
 my $prefix;
@@ -87,7 +125,6 @@ sub prefix_words ($)
 sub prefix_assignment ($$)
 {
   my ($lhs_and_assign_op, $rhs) = @_;
-  my $res;
 
   # Some variables are initialized by gnulib.mk, and we don't want
   # that.  Change '=' to '+='.
@@ -95,21 +132,35 @@ sub prefix_assignment ($$)
     {
       # Do not change the RHS, which specifies the GPERF program.
     }
+  # Don't change variables such as HAVE_INCLUDE_NEXT.
+  elsif ($lhs_and_assign_op =~ /^HAVE_/)
+    {
+    }
   elsif ($lhs_and_assign_op =~
       /^(SUBDIRS|EXTRA_DIST|BUILT_SOURCES|SUFFIXES|MOSTLYCLEANFILES
-         |CLEANFILES|DISTCLEANFILES|MAINTAINERCLEANFILES|AM_CFLAGS
-         |AM_CPPFLAGS|AM_GNU_GETTEXT)\ =/x)
+         |CLEANFILES|DISTCLEANFILES|MAINTAINERCLEANFILES
+         |AM_GNU_GETTEXT)\ =/x)
     {
       $lhs_and_assign_op =~ s/=/+=/;
     }
+  # We don't want things such as AM_CPPFLAGS +=
+  # -DDEFAULT_TEXT_DOMAIN=\"bison-gnulib\" to apply to the whole
+  # Makefile.in: scope it to the library: libbison_a_CPPFLAGS =
+  # $(AM_CPPFLAGS) -DDEFAULT_TEXT_DOMAIN=\"bison-gnulib\".
+  elsif ($lhs_and_assign_op =~
+      /^(AM_CFLAGS|AM_CPPFLAGS)\ \+?=/x)
+    {
+      $lhs_and_assign_op =~ s/^AM_(\w+)\ \+?=/${lib_name}_a_$1 =/;
+      $rhs = " \$(AM_$1)$rhs";
+    }
   # We don't want to inherit gnulib's AUTOMAKE_OPTIONS, comment them.
   elsif ($lhs_and_assign_op =~ /^AUTOMAKE_OPTIONS =/)
     {
       $lhs_and_assign_op =~ s/^/# /;
     }
+  # Elide any SUFFIXES assignment or concatenation.
   elsif ($lhs_and_assign_op =~ /^SUFFIXES /)
     {
-      # Elide any SUFFIXES assignment or concatenation.
       $lhs_and_assign_op =~ s/^/# /;
     }
   # The words are (probably) paths to files in lib/: prefix them.
@@ -118,11 +169,11 @@ sub prefix_assignment ($$)
       $rhs = prefix_words($rhs)
     }
 
-  # Variables which name depend on the location: libbison_a_SOURCES =>
+  # Variables whose name depend on the location: libbison_a_SOURCES =>
   # lib_libbison_a_SOURCES.
   $lhs_and_assign_op =~ s/($lib_name)/lib_$1/g;
 
-  return $lhs_and_assign_op . $rhs;
+  $lhs_and_assign_op . $rhs;
 }
 
 # prefix $CONTENTS
@@ -222,6 +273,7 @@ sub process ($)
 ## cperl-merge-trailing-else: nil
 ## cperl-continued-statement-offset: 2
 ## eval: (add-hook 'before-save-hook 'time-stamp)
+## time-stamp-line-limit: 50
 ## time-stamp-start: "my $VERSION = '"
 ## time-stamp-format: "%:y-%02m-%02d %02H:%02M"
 ## time-stamp-time-zone: "UTC0"
diff --git a/build-aux/test-driver b/build-aux/test-driver
index b8521a4..89dba1e 100755
--- a/build-aux/test-driver
+++ b/build-aux/test-driver
@@ -3,7 +3,7 @@
 
 scriptversion=2018-03-07.03; # UTC
 
-# Copyright (C) 2011-2018 Free Software Foundation, Inc.
+# Copyright (C) 2011-2020 Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/texinfo.tex b/build-aux/texinfo.tex
index 5840aff..1ea515b 100644
--- a/build-aux/texinfo.tex
+++ b/build-aux/texinfo.tex
@@ -1,14 +1,11 @@
 % texinfo.tex -- TeX macros to handle Texinfo files.
-% 
+%
 % Load plain if necessary, i.e., if running under initex.
 \expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi
 %
-\def\texinfoversion{2018-09-21.20}
+\def\texinfoversion{2019-09-24.13}
 %
-% Copyright 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995,
-% 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
-% 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018
-% Free Software Foundation, Inc.
+% Copyright 1985, 1986, 1988, 1990-2019 Free Software Foundation, Inc.
 %
 % This texinfo.tex file is free software: you can redistribute it and/or
 % modify it under the terms of the GNU General Public License as
@@ -221,7 +218,7 @@
 % @errormsg{MSG}.  Do the index-like expansions on MSG, but if things
 % aren't perfect, it's not the end of the world, being an error message,
 % after all.
-% 
+%
 \def\errormsg{\begingroup \indexnofonts \doerrormsg}
 \def\doerrormsg#1{\errmessage{#1}}
 
@@ -244,17 +241,7 @@
 %
 \def\finalout{\overfullrule=0pt }
 
-% Do @cropmarks to get crop marks.
-%
-\newif\ifcropmarks
-\let\cropmarks = \cropmarkstrue
-%
-% Dimensions to add cropmarks at corners.
-% Added by P. A. MacKay, 12 Nov. 1986
-%
 \newdimen\outerhsize \newdimen\outervsize % set by the paper size routines
-\newdimen\cornerlong  \cornerlong=1pc
-\newdimen\cornerthick \cornerthick=.3pt
 \newdimen\topandbottommargin \topandbottommargin=.75in
 
 % Output a mark which sets \thischapter, \thissection and \thiscolor.
@@ -270,8 +257,8 @@
 
 % \domark is called twice inside \chapmacro, to add one
 % mark before the section break, and one after.
-%   In the second call \prevchapterdefs is the same as \lastchapterdefs,
-% and \prevsectiondefs is the same as \lastsectiondefs.
+%   In the second call \prevchapterdefs is the same as \currentchapterdefs,
+% and \prevsectiondefs is the same as \currentsectiondefs.
 %   Then if the page is not broken at the mark, some of the previous
 % section appears on the page, and we can get the name of this section
 % from \firstmark for @everyheadingmarks top.
@@ -279,11 +266,11 @@
 %
 % See page 260 of The TeXbook.
 \def\domark{%
-  \toks0=\expandafter{\lastchapterdefs}%
-  \toks2=\expandafter{\lastsectiondefs}%
+  \toks0=\expandafter{\currentchapterdefs}%
+  \toks2=\expandafter{\currentsectiondefs}%
   \toks4=\expandafter{\prevchapterdefs}%
   \toks6=\expandafter{\prevsectiondefs}%
-  \toks8=\expandafter{\lastcolordefs}%
+  \toks8=\expandafter{\currentcolordefs}%
   \mark{%
                    \the\toks0 \the\toks2  % 0: marks for @everyheadingmarks top
       \noexpand\or \the\toks4 \the\toks6  % 1: for @everyheadingmarks bottom
@@ -300,19 +287,19 @@
 % @setcolor (or @url, or @link, etc.) between @contents and the very
 % first @chapter.
 \def\gettopheadingmarks{%
-  \ifcase0\topmark\fi
+  \ifcase0\the\savedtopmark\fi
   \ifx\thischapter\empty \ifcase0\firstmark\fi \fi
 }
 \def\getbottomheadingmarks{\ifcase1\botmark\fi}
-\def\getcolormarks{\ifcase2\topmark\fi}
+\def\getcolormarks{\ifcase2\the\savedtopmark\fi}
 
 % Avoid "undefined control sequence" errors.
-\def\lastchapterdefs{}
-\def\lastsectiondefs{}
-\def\lastsection{}
+\def\currentchapterdefs{}
+\def\currentsectiondefs{}
+\def\currentsection{}
 \def\prevchapterdefs{}
 \def\prevsectiondefs{}
-\def\lastcolordefs{}
+\def\currentcolordefs{}
 
 % Margin to add to right of even pages, to left of odd pages.
 \newdimen\bindingoffset
@@ -322,50 +309,75 @@
 % Main output routine.
 %
 \chardef\PAGE = 255
-\output = {\onepageout{\pagecontents\PAGE}}
+\newtoks\defaultoutput
+\defaultoutput = {\savetopmark\onepageout{\pagecontents\PAGE}}
+\output=\expandafter{\the\defaultoutput}
 
 \newbox\headlinebox
 \newbox\footlinebox
 
+% When outputting the double column layout for indices, an output routine
+% is run several times, which hides the original value of \topmark.  This
+% can lead to a page heading being output and duplicating the chapter heading
+% of the index.  Hence, save the contents of \topmark at the beginning of
+% the output routine.  The saved contents are valid until we actually
+% \shipout a page.
+%
+% (We used to run a short output routine to actually set \topmark and
+% \firstmark to the right values, but if this was called with an empty page
+% containing whatsits for writing index entries, the whatsits would be thrown
+% away and the index auxiliary file would remain empty.)
+%
+\newtoks\savedtopmark
+\newif\iftopmarksaved
+\topmarksavedtrue
+\def\savetopmark{%
+  \iftopmarksaved\else
+    \global\savedtopmark=\expandafter{\topmark}%
+    \global\topmarksavedtrue
+  \fi
+}
+
 % \onepageout takes a vbox as an argument.
-% \shipout a vbox for a single page, adding an optional header, footer,
-% cropmarks, and footnote.  This also causes index entries for this page
-% to be written to the auxiliary files.
+% \shipout a vbox for a single page, adding an optional header, footer
+% and footnote.  This also causes index entries for this page to be written
+% to the auxiliary files.
 %
 \def\onepageout#1{%
-  \ifcropmarks \hoffset=0pt \else \hoffset=\normaloffset \fi
+  \hoffset=\normaloffset
   %
   \ifodd\pageno  \advance\hoffset by \bindingoffset
   \else \advance\hoffset by -\bindingoffset\fi
   %
-  % Common context changes for both heading and footing.
-  % Do this outside of the \shipout so @code etc. will be expanded in
-  % the headline as they should be, not taken literally (outputting ''code).
-  \def\commmonheadfootline{\let\hsize=\txipagewidth \texinfochars}
-  %
   % Retrieve the information for the headings from the marks in the page,
   % and call Plain TeX's \makeheadline and \makefootline, which use the
   % values in \headline and \footline.
   %
   % This is used to check if we are on the first page of a chapter.
-  \ifcase1\topmark\fi
+  \ifcase1\the\savedtopmark\fi
   \let\prevchaptername\thischaptername
   \ifcase0\firstmark\fi
   \let\curchaptername\thischaptername
   %
   \ifodd\pageno \getoddheadingmarks \else \getevenheadingmarks \fi
-  \ifodd\pageno \getoddfootingmarks \else \getevenfootingmarks \fi
   %
   \ifx\curchaptername\prevchaptername
     \let\thischapterheading\thischapter
   \else
     % \thischapterheading is the same as \thischapter except it is blank
-    % for the first page of a chapter.  This is to prevent the chapter name 
+    % for the first page of a chapter.  This is to prevent the chapter name
     % being shown twice.
     \def\thischapterheading{}%
   \fi
   %
+  % Common context changes for both heading and footing.
+  % Do this outside of the \shipout so @code etc. will be expanded in
+  % the headline as they should be, not taken literally (outputting ''code).
+  \def\commmonheadfootline{\let\hsize=\txipagewidth \texinfochars}
+  %
   \global\setbox\headlinebox = \vbox{\commmonheadfootline \makeheadline}%
+  %
+  \ifodd\pageno \getoddfootingmarks \else \getevenfootingmarks \fi
   \global\setbox\footlinebox = \vbox{\commmonheadfootline \makefootline}%
   %
   {%
@@ -374,37 +386,12 @@
     % take effect in \write's, yet the group defined by the \vbox ends
     % before the \shipout runs.
     %
-    \indexdummies         % don't expand commands in the output.
-    \normalturnoffactive  % \ in index entries must not stay \, e.g., if
-               % the page break happens to be in the middle of an example.
-               % We don't want .vr (or whatever) entries like this:
-               % \entry{{\indexbackslash }acronym}{32}{\code {\acronym}}
-               % "\acronym" won't work when it's read back in;
-               % it needs to be
-               % {\code {{\backslashcurfont }acronym}
+    \atdummies         % don't expand commands in the output.
+    \turnoffactive
     \shipout\vbox{%
       % Do this early so pdf references go to the beginning of the page.
       \ifpdfmakepagedest \pdfdest name{\the\pageno} xyz\fi
       %
-      \ifcropmarks \vbox to \outervsize\bgroup
-        \hsize = \outerhsize
-        \vskip-\topandbottommargin
-        \vtop to0pt{%
-          \line{\ewtop\hfil\ewtop}%
-          \nointerlineskip
-          \line{%
-            \vbox{\moveleft\cornerthick\nstop}%
-            \hfill
-            \vbox{\moveright\cornerthick\nstop}%
-          }%
-          \vss}%
-        \vskip\topandbottommargin
-        \line\bgroup
-          \hfil % center the page within the outer (page) hsize.
-          \ifodd\pageno\hskip\bindingoffset\fi
-          \vbox\bgroup
-      \fi
-      %
       \unvbox\headlinebox
       \pagebody{#1}%
       \ifdim\ht\footlinebox > 0pt
@@ -415,24 +402,9 @@
         \unvbox\footlinebox
       \fi
       %
-      \ifcropmarks
-          \egroup % end of \vbox\bgroup
-        \hfil\egroup % end of (centering) \line\bgroup
-        \vskip\topandbottommargin plus1fill minus1fill
-        \boxmaxdepth = \cornerthick
-        \vbox to0pt{\vss
-          \line{%
-            \vbox{\moveleft\cornerthick\nsbot}%
-            \hfill
-            \vbox{\moveright\cornerthick\nsbot}%
-          }%
-          \nointerlineskip
-          \line{\ewbot\hfil\ewbot}%
-        }%
-      \egroup % \vbox from first cropmarks clause
-      \fi
-    }% end of \shipout\vbox
-  }% end of group with \indexdummies
+    }%
+  }%
+  \global\topmarksavedfalse
   \advancepageno
   \ifnum\outputpenalty>-20000 \else\dosupereject\fi
 }
@@ -451,17 +423,6 @@
 \ifr@ggedbottom \kern-\dimen@ \vfil \fi}
 }
 
-% Here are the rules for the cropmarks.  Note that they are
-% offset so that the space between them is truly \outerhsize or \outervsize
-% (P. A. MacKay, 12 November, 1986)
-%
-\def\ewtop{\vrule height\cornerthick depth0pt width\cornerlong}
-\def\nstop{\vbox
-  {\hrule height\cornerthick depth\cornerlong width\cornerthick}}
-\def\ewbot{\vrule height0pt depth\cornerthick width\cornerlong}
-\def\nsbot{\vbox
-  {\hrule height\cornerlong depth\cornerthick width\cornerthick}}
-
 
 % Argument parsing
 
@@ -487,11 +448,10 @@
   }%
 }
 
-% First remove any @comment, then any @c comment.  Also remove a @texinfoc
-% comment (see \scanmacro for details).  Pass the result on to \argcheckspaces.
+% First remove any @comment, then any @c comment.  Pass the result on to
+% \argcheckspaces.
 \def\argremovecomment#1\comment#2\ArgTerm{\argremovec #1\c\ArgTerm}
-\def\argremovec#1\c#2\ArgTerm{\argremovetexinfoc #1\texinfoc\ArgTerm}
-\def\argremovetexinfoc#1\texinfoc#2\ArgTerm{\argcheckspaces#1\^^M\ArgTerm}
+\def\argremovec#1\c#2\ArgTerm{\argcheckspaces#1\^^M\ArgTerm}
 
 % Each occurrence of `\^^M' or `<space>\^^M' is replaced by a single space.
 %
@@ -1092,7 +1052,7 @@ where each line of input produces a line of output.}
             tex.sprint(
               string.format(string.char(0x5c) .. string.char(0x25) .. '03o' ..
                             string.char(0x5c) .. string.char(0x25) .. '03o',
-                            (c / 256), (c % 256)))
+                            math.floor(c / 256), math.floor(c % 256)))
           else
             c = c - 0x10000
             local c_hi = c / 1024 + 0xd800
@@ -1102,8 +1062,8 @@ where each line of input produces a line of output.}
                             string.char(0x5c) .. string.char(0x25) .. '03o' ..
                             string.char(0x5c) .. string.char(0x25) .. '03o' ..
                             string.char(0x5c) .. string.char(0x25) .. '03o',
-                            (c_hi / 256), (c_hi % 256),
-                            (c_lo / 256), (c_lo % 256)))
+                            math.floor(c_hi / 256), math.floor(c_hi % 256),
+                            math.floor(c_lo / 256), math.floor(c_lo % 256)))
           end
         end
       end
@@ -1116,15 +1076,19 @@ where each line of input produces a line of output.}
       function PDFescstr(str)
         for c in string.bytes(str) do
           if c <= 0x20 or c >= 0x80 or c == 0x28 or c == 0x29 or c == 0x5c then
-            tex.sprint(
+            tex.sprint(-2,
               string.format(string.char(0x5c) .. string.char(0x25) .. '03o',
                             c))
           else
-            tex.sprint(string.char(c))
+            tex.sprint(-2, string.char(c))
           end
         end
       end
     }
+    % The -2 in the arguments here gives all the input to TeX catcode 12
+    % (other) or 10 (space), preventing undefined control sequence errors. See
+    % https://lists.gnu.org/archive/html/bug-texinfo/2019-08/msg00031.html
+    %
   \endgroup
   \def\pdfescapestring#1{\directlua{PDFescstr('\luaescapestring{#1}')}}
   \ifnum\luatexversion>84
@@ -1163,11 +1127,21 @@ where each line of input produces a line of output.}
   \fi
 \fi
 
+\newif\ifpdforxetex
+\pdforxetexfalse
+\ifpdf
+  \pdforxetextrue
+\fi
+\ifx\XeTeXrevision\thisisundefined\else
+  \pdforxetextrue
+\fi
+
+
 % PDF uses PostScript string constants for the names of xref targets,
 % for display in the outlines, and in other places.  Thus, we have to
 % double any backslashes.  Otherwise, a name like "\node" will be
 % interpreted as a newline (\n), followed by o, d, e.  Not good.
-% 
+%
 % See http://www.ntg.nl/pipermail/ntg-pdftex/2004-July/000654.html and
 % related messages.  The final outcome is that it is up to the TeX user
 % to double the backslashes and otherwise make the string valid, so
@@ -1219,7 +1193,7 @@ output) for that.)}
   % Set color, and create a mark which defines \thiscolor accordingly,
   % so that \makeheadline knows which color to restore.
   \def\setcolor#1{%
-    \xdef\lastcolordefs{\gdef\noexpand\thiscolor{#1}}%
+    \xdef\currentcolordefs{\gdef\noexpand\thiscolor{#1}}%
     \domark
     \pdfsetcolor{#1}%
   }
@@ -1227,7 +1201,7 @@ output) for that.)}
   \def\maincolor{\rgbBlack}
   \pdfsetcolor{\maincolor}
   \edef\thiscolor{\maincolor}
-  \def\lastcolordefs{}
+  \def\currentcolordefs{}
   %
   \def\makefootline{%
     \baselineskip24pt
@@ -1472,7 +1446,7 @@ output) for that.)}
       % their "best" equivalent, based on the @documentencoding.  Too
       % much work for too little return.  Just use the ASCII equivalents
       % we use for the index sort strings.
-      % 
+      %
       \indexnofonts
       \setupdatafile
       % We can have normal brace characters in the PDF outlines, unlike
@@ -1605,7 +1579,7 @@ output) for that.)}
   % Set color, and create a mark which defines \thiscolor accordingly,
   % so that \makeheadline knows which color to restore.
   \def\setcolor#1{%
-    \xdef\lastcolordefs{\gdef\noexpand\thiscolor{#1}}%
+    \xdef\currentcolordefs{\gdef\noexpand\thiscolor{#1}}%
     \domark
     \pdfsetcolor{#1}%
   }
@@ -1613,7 +1587,7 @@ output) for that.)}
   \def\maincolor{\rgbBlack}
   \pdfsetcolor{\maincolor}
   \edef\thiscolor{\maincolor}
-  \def\lastcolordefs{}
+  \def\currentcolordefs{}
   %
   \def\makefootline{%
     \baselineskip24pt
@@ -2205,7 +2179,7 @@ end
 % A few fonts for @defun names and args.
 \setfont\defbf\bfshape{10}{\magstep1}{OT1}
 \setfont\deftt\ttshape{10}{\magstep1}{OT1TT}
-\setfont\defsl\slshape{10}{\magstep1}{OT1TT}
+\setfont\defsl\slshape{10}{\magstep1}{OT1}
 \setfont\defttsl\ttslshape{10}{\magstep1}{OT1TT}
 \def\df{\let\ttfont=\deftt \let\bffont = \defbf
 \let\ttslfont=\defttsl \let\slfont=\defsl \bf}
@@ -2353,7 +2327,7 @@ end
 % A few fonts for @defun names and args.
 \setfont\defbf\bfshape{10}{\magstephalf}{OT1}
 \setfont\deftt\ttshape{10}{\magstephalf}{OT1TT}
-\setfont\defsl\slshape{10}{\magstephalf}{OT1TT}
+\setfont\defsl\slshape{10}{\magstephalf}{OT1}
 \setfont\defttsl\ttslshape{10}{\magstephalf}{OT1TT}
 \def\df{\let\ttfont=\deftt \let\bffont = \defbf
 \let\slfont=\defsl \let\ttslfont=\defttsl \bf}
@@ -2756,7 +2730,7 @@ end
 }
 
 % Commands to set the quote options.
-% 
+%
 \parseargdef\codequoteundirected{%
   \def\temp{#1}%
   \ifx\temp\onword
@@ -2797,7 +2771,7 @@ end
 % If we are in a monospaced environment, however, 1) always use \ttsl,
 % and 2) do not add an italic correction.
 \def\dosmartslant#1#2{%
-  \ifusingtt 
+  \ifusingtt
     {{\ttsl #2}\let\next=\relax}%
     {\def\next{{#1#2}\futurelet\next\smartitaliccorrection}}%
   \next
@@ -2876,7 +2850,7 @@ end
 
 % @t, explicit typewriter.
 \def\t#1{%
-  {\tt \rawbackslash \plainfrenchspacing #1}%
+  {\tt \plainfrenchspacing #1}%
   \null
 }
 
@@ -2903,7 +2877,6 @@ end
     % Turn off hyphenation.
     \nohyphenation
     %
-    \rawbackslash
     \plainfrenchspacing
     #1%
   }%
@@ -2945,14 +2918,14 @@ end
   \gdef\codedash{\futurelet\next\codedashfinish}
   \gdef\codedashfinish{%
     \normaldash % always output the dash character itself.
-    % 
+    %
     % Now, output a discretionary to allow a line break, unless
     % (a) the next character is a -, or
     % (b) the preceding character is a -.
     % E.g., given --posix, we do not want to allow a break after either -.
     % Given --foo-bar, we do want to allow a break between the - and the b.
     \ifx\next\codedash \else
-      \ifx\codedashprev\codedash 
+      \ifx\codedashprev\codedash
       \else \discretionary{}{}{}\fi
     \fi
     % we need the space after the = for the case when \next itself is a
@@ -3034,7 +3007,7 @@ end
         % For pdfTeX and LuaTeX
         \ifurefurlonlylink
           % PDF plus option to not display url, show just arg
-          \unhbox0             
+          \unhbox0
         \else
           % PDF, normally display both arg and url for consistency,
           % visibility, if the pdf is eventually used to print, etc.
@@ -3047,7 +3020,7 @@ end
           % For XeTeX
           \ifurefurlonlylink
             % PDF plus option to not display url, show just arg
-            \unhbox0             
+            \unhbox0
           \else
             % PDF, normally display both arg and url for consistency,
             % visibility, if the pdf is eventually used to print, etc.
@@ -3090,41 +3063,33 @@ end
   \global\def/{\normalslash}
 }
 
-% we put a little stretch before and after the breakable chars, to help
-% line breaking of long url's.  The unequal skips make look better in
-% cmtt at least, especially for dots.
-\def\urefprestretchamount{.13em}
-\def\urefpoststretchamount{.1em}
-\def\urefprestretch{\urefprebreak \hskip0pt plus\urefprestretchamount\relax}
-\def\urefpoststretch{\urefpostbreak \hskip0pt plus\urefprestretchamount\relax}
-%
-\def\urefcodeamp{\urefprestretch \&\urefpoststretch}
-\def\urefcodedot{\urefprestretch .\urefpoststretch}
-\def\urefcodehash{\urefprestretch \#\urefpoststretch}
-\def\urefcodequest{\urefprestretch ?\urefpoststretch}
+\def\urefcodeamp{\urefprebreak \&\urefpostbreak}
+\def\urefcodedot{\urefprebreak .\urefpostbreak}
+\def\urefcodehash{\urefprebreak \#\urefpostbreak}
+\def\urefcodequest{\urefprebreak ?\urefpostbreak}
 \def\urefcodeslash{\futurelet\next\urefcodeslashfinish}
 {
   \catcode`\/=\active
   \global\def\urefcodeslashfinish{%
-    \urefprestretch \slashChar
+    \urefprebreak \slashChar
     % Allow line break only after the final / in a sequence of
     % slashes, to avoid line break between the slashes in http://.
-    \ifx\next/\else \urefpoststretch \fi
+    \ifx\next/\else \urefpostbreak \fi
   }
 }
 
-% One more complication: by default we'll break after the special
-% characters, but some people like to break before the special chars, so
-% allow that.  Also allow no breaking at all, for manual control.
-% 
+% By default we'll break after the special characters, but some people like to
+% break before the special chars, so allow that.  Also allow no breaking at
+% all, for manual control.
+%
 \parseargdef\urefbreakstyle{%
   \def\txiarg{#1}%
   \ifx\txiarg\wordnone
     \def\urefprebreak{\nobreak}\def\urefpostbreak{\nobreak}
   \else\ifx\txiarg\wordbefore
-    \def\urefprebreak{\allowbreak}\def\urefpostbreak{\nobreak}
+    \def\urefprebreak{\urefallowbreak}\def\urefpostbreak{\nobreak}
   \else\ifx\txiarg\wordafter
-    \def\urefprebreak{\nobreak}\def\urefpostbreak{\allowbreak}
+    \def\urefprebreak{\nobreak}\def\urefpostbreak{\urefallowbreak}
   \else
     \errhelp = \EMsimple
     \errmessage{Unknown @urefbreakstyle setting `\txiarg'}%
@@ -3134,6 +3099,19 @@ end
 \def\wordbefore{before}
 \def\wordnone{none}
 
+% Allow a ragged right output to aid breaking long URL's.  There can
+% be a break at the \allowbreak with no extra glue (if the existing stretch in
+% the line is sufficent), a break at the \penalty100 with extra glue added
+% at the end of the line, or no break at all here.
+%   Changing the value of the penalty and/or the amount of stretch affects how
+% preferrable one choice is over the other.
+\def\urefallowbreak{%
+  \allowbreak
+  \hskip 0pt plus 4 em\relax
+  \penalty100
+  \hskip 0pt plus -4 em\relax
+}
+
 \urefbreakstyle after
 
 % @url synonym for @uref, since that's how everyone uses it.
@@ -3144,7 +3122,7 @@ end
 % So now @email is just like @uref, unless we are pdf.
 %
 %\def\email#1{\angleleft{\tt #1}\angleright}
-\ifpdf
+\ifpdforxetex
   \def\email#1{\doemail#1,,\finish}
   \def\doemail#1,#2,#3\finish{\begingroup
     \unsepspaces
@@ -3154,18 +3132,7 @@ end
     \endlink
   \endgroup}
 \else
-  \ifx\XeTeXrevision\thisisundefined
-    \let\email=\uref
-  \else
-    \def\email#1{\doemail#1,,\finish}
-    \def\doemail#1,#2,#3\finish{\begingroup
-      \unsepspaces
-      \pdfurl{mailto:#1}%
-      \setbox0 = \hbox{\ignorespaces #2}%
-      \ifdim\wd0>0pt\unhbox0\else\code{#1}\fi
-      \endlink
-    \endgroup}
-  \fi
+  \let\email=\uref
 \fi
 
 % @kbdinputstyle -- arg is `distinct' (@kbd uses slanted tty font always),
@@ -3341,7 +3308,7 @@ end
 % @inlinefmt{FMTNAME,PROCESSED-TEXT} and @inlineraw{FMTNAME,RAW-TEXT}.
 % Ignore unless FMTNAME == tex; then it is like @iftex and @tex,
 % except specified as a normal braced arg, so no newlines to worry about.
-% 
+%
 \def\outfmtnametex{tex}
 %
 \long\def\inlinefmt#1{\doinlinefmt #1,\finish}
@@ -3349,7 +3316,7 @@ end
   \def\inlinefmtname{#1}%
   \ifx\inlinefmtname\outfmtnametex \ignorespaces #2\fi
 }
-% 
+%
 % @inlinefmtifelse{FMTNAME,THEN-TEXT,ELSE-TEXT} expands THEN-TEXT if
 % FMTNAME is tex, else ELSE-TEXT.
 \long\def\inlinefmtifelse#1{\doinlinefmtifelse #1,,,\finish}
@@ -3365,7 +3332,7 @@ end
 % *right* brace they would have to use a command anyway, so they may as
 % well use a command to get a left brace too.  We could re-use the
 % delimiter character idea from \verb, but it seems like overkill.
-% 
+%
 \long\def\inlineraw{\tex \doinlineraw}
 \long\def\doinlineraw#1{\doinlinerawtwo #1,\finish}
 \def\doinlinerawtwo#1,#2,\finish{%
@@ -3642,7 +3609,7 @@ end
 % for non-CM glyphs.  That is ec* for regular text and tc* for the text
 % companion symbols (LaTeX TS1 encoding).  Both are part of the ec
 % package and follow the same conventions.
-% 
+%
 \def\ecfont{\etcfont{e}}
 \def\tcfont{\etcfont{t}}
 %
@@ -3714,7 +3681,7 @@ end
               after the title page.}}%
 \def\setshortcontentsaftertitlepage{%
   \errmessage{@setshortcontentsaftertitlepage has been removed as a Texinfo
-              command; move your @shortcontents and @contents commands if you 
+              command; move your @shortcontents and @contents commands if you
               want the contents after the title page.}}%
 
 \parseargdef\shorttitlepage{%
@@ -3769,7 +3736,7 @@ end
 % don't worry much about spacing, ragged right.  This should be used
 % inside a \vbox, and fonts need to be set appropriately first. \par should
 % be specified before the end of the \vbox, since a vbox is a group.
-% 
+%
 \def\raggedtitlesettings{%
   \rm
   \hyphenpenalty=10000
@@ -4392,7 +4359,7 @@ end
 }
 
 % multitable-only commands.
-% 
+%
 % @headitem starts a heading row, which we typeset in bold.  Assignments
 % have to be global since we are inside the implicit group of an
 % alignment entry.  \everycr below resets \everytab so we don't have to
@@ -4699,19 +4666,6 @@ end
   }
 }
 
-% We have this subroutine so that we can handle at least some @value's
-% properly in indexes (we call \makevalueexpandable in \indexdummies).
-% The command has to be fully expandable (if the variable is set), since
-% the result winds up in the index file.  This means that if the
-% variable's value contains other Texinfo commands, it's almost certain
-% it will fail (although perhaps we could fix that with sufficient work
-% to do a one-level expansion on the result, instead of complete).
-% 
-% Unfortunately, this has the consequence that when _ is in the *value*
-% of an @set, it does not print properly in the roman fonts (get the cmr
-% dot accent at position 126 instead).  No fix comes to mind, and it's
-% been this way since 2003 or earlier, so just ignore it.
-% 
 \def\expandablevalue#1{%
   \expandafter\ifx\csname SET#1\endcsname\relax
     {[No value for ``#1'']}%
@@ -4724,13 +4678,13 @@ end
 % Like \expandablevalue, but completely expandable (the \message in the
 % definition above operates at the execution level of TeX).  Used when
 % writing to auxiliary files, due to the expansion that \write does.
-% If flag is undefined, pass through an unexpanded @value command: maybe it 
+% If flag is undefined, pass through an unexpanded @value command: maybe it
 % will be set by the time it is read back in.
 %
 % NB flag names containing - or _ may not work here.
 \def\dummyvalue#1{%
   \expandafter\ifx\csname SET#1\endcsname\relax
-    \noexpand\value{#1}%
+    \string\value{#1}%
   \else
     \csname SET#1\endcsname
   \fi
@@ -4740,7 +4694,7 @@ end
 % if possible, otherwise sort late.
 \def\indexnofontsvalue#1{%
   \expandafter\ifx\csname SET#1\endcsname\relax
-    ZZZZZZZ
+    ZZZZZZZ%
   \else
     \csname SET#1\endcsname
   \fi
@@ -4748,7 +4702,7 @@ end
 
 % @ifset VAR ... @end ifset reads the `...' iff VAR has been defined
 % with @set.
-% 
+%
 % To get the special treatment we need for `@end ifset,' we call
 % \makecond and then redefine.
 %
@@ -4781,7 +4735,7 @@ end
 % without the @) is in fact defined.  We can only feasibly check at the
 % TeX level, so something like `mathcode' is going to considered
 % defined even though it is not a Texinfo command.
-% 
+%
 \makecond{ifcommanddefined}
 \def\ifcommanddefined{\parsearg{\doifcmddefined{\let\next=\ifcmddefinedfail}}}
 %
@@ -4889,30 +4843,16 @@ end
 \def\docodeindex#1{\edef\indexname{#1}\parsearg\docodeindexxxx}
 \def\docodeindexxxx #1{\doind{\indexname}{\code{#1}}}
 
-
-% Used when writing an index entry out to an index file to prevent
-% expansion of Texinfo commands that can appear in an index entry.
-%
-\def\indexdummies{%
-  \escapechar = `\\     % use backslash in output files.
-  \definedummyletter\@%
-  \definedummyletter\ %
-  %
-  % For texindex which always views { and } as separators.
-  \def\{{\lbracechar{}}%
-  \def\}{\rbracechar{}}%
-  %
-  % Do the redefinitions.
-  \definedummies
-}
 
-% Used for the aux and toc files, where @ is the escape character.
+% Used for the aux, toc and index files to prevent expansion of Texinfo
+% commands.
 %
 \def\atdummies{%
   \definedummyletter\@%
   \definedummyletter\ %
   \definedummyletter\{%
   \definedummyletter\}%
+  \definedummyletter\&%
   %
   % Do the redefinitions.
   \definedummies
@@ -4936,8 +4876,7 @@ end
 \def\definedummyletter#1{\def#1{\string#1}}%
 \let\definedummyaccent\definedummyletter
 
-% Called from \indexdummies and \atdummies, to effectively prevent
-% the expansion of commands.
+% Called from \atdummies to prevent the expansion of commands.
 %
 \def\definedummies{%
   %
@@ -4984,8 +4923,10 @@ end
   \definedummyword\TeX
   %
   % Assorted special characters.
+  \definedummyword\ampchar
   \definedummyword\atchar
   \definedummyword\arrow
+  \definedummyword\backslashchar
   \definedummyword\bullet
   \definedummyword\comma
   \definedummyword\copyright
@@ -5022,6 +4963,8 @@ end
   \definedummyword\sup
   \definedummyword\textdegree
   %
+  \definedummyword\subentry
+  %
   % We want to disable all macros so that they are not expanded by \write.
   \macrolist
   \let\value\dummyvalue
@@ -5102,11 +5045,10 @@ end
   \commondummyword\xref
 }
 
-% For testing: output @{ and @} in index sort strings as \{ and \}.
-\newif\ifusebracesinindexes
-
 \let\indexlbrace\relax
 \let\indexrbrace\relax
+\let\indexatchar\relax
+\let\indexbackslash\relax
 
 {\catcode`\@=0
 \catcode`\\=13
@@ -5140,10 +5082,8 @@ end
   }
 
   \gdef\indexnonalnumreappear{%
-    \useindexbackslash
     \let-\normaldash
     \let<\normalless
-    \def\@{@}%
   }
 }
 
@@ -5251,39 +5191,19 @@ end
 }
 \def\defglyph#1#2{\def#1##1{#2}} % see above
 
-
 
 
-\let\SETmarginindex=\relax % put index entries in margin (undocumented)?
 
-% Most index entries go through here, but \dosubind is the general case.
 % #1 is the index name, #2 is the entry text.
-\def\doind#1#2{\dosubind{#1}{#2}{}}
-
-% There is also \dosubind {index}{topic}{subtopic}
-% which makes an entry in a two-level index such as the operation index.
-% TODO: Two-level index?  Operation index?
-
-% Workhorse for all indexes.
-% #1 is name of index, #2 is stuff to put there, #3 is subentry --
-% empty if called from \doind, as we usually are (the main exception
-% is with most defuns, which call us directly).
-%
-\def\dosubind#1#2#3{%
+\def\doind#1#2{%
   \iflinks
   {%
-    \requireopenindexfile{#1}%
-    % Store the main index entry text (including the third arg).
-    \toks0 = {#2}%
-    % If third arg is present, precede it with a space.
-    \def\thirdarg{#3}%
-    \ifx\thirdarg\empty \else
-      \toks0 = \expandafter{\the\toks0 \space #3}%
-    \fi
     %
+    \requireopenindexfile{#1}%
     \edef\writeto{\csname#1indfile\endcsname}%
     %
-    \safewhatsit\dosubindwrite
+    \def\indextext{#2}%
+    \safewhatsit\doindwrite
   }%
   \fi
 }
@@ -5298,28 +5218,14 @@ end
   \ifx\suffix\indexisfl\def\suffix{f1}\fi
   % Open the file
   \immediate\openout\csname#1indfile\endcsname \jobname.\suffix
-  % Using \immediate above here prevents an object entering into the current 
+  % Using \immediate above here prevents an object entering into the current
   % box, which could confound checks such as those in \safewhatsit for
   % preceding skips.
   \typeout{Writing index file \jobname.\suffix}%
 \fi}
 \def\indexisfl{fl}
 
-% Output \ as {\indexbackslash}, because \ is an escape character in
-% the index files.
-\let\indexbackslash=\relax
-{\catcode`\@=0 \catcode`\\=\active
-  @gdef@useindexbackslash{@def\{{@indexbackslash}}}
-}
-
-% Definition for writing index entry text.
-\def\sortas#1{\ignorespaces}%
-
-% Definition for writing index entry sort key.  Should occur at the at
-% the beginning of the index entry, like
-%     @cindex @sortas{september} \september
-% The \ignorespaces takes care of following space, but there's no way
-% to remove space before it.
+% Definition for writing index entry sort key.
 {
 \catcode`\-=13
 \gdef\indexwritesortas{%
@@ -5330,51 +5236,150 @@ end
   \xdef\indexsortkey{#1}\endgroup}
 }
 
+\def\indexwriteseealso#1{
+  \gdef\pagenumbertext{\string\seealso{#1}}%
+}
+\def\indexwriteseeentry#1{
+  \gdef\pagenumbertext{\string\seeentry{#1}}%
+}
+
+% The default definitions
+\def\sortas#1{}%
+\def\seealso#1{\i{\putwordSeeAlso}\ #1}% for sorted index file only
+\def\putwordSeeAlso{See also}
+\def\seeentry#1{\i{\putwordSee}\ #1}% for sorted index file only
+
 
-% Write the entry in \toks0 to the index file.
+% Given index entry text like "aaa @subentry bbb @sortas{ZZZ}":
+%   * Set \bracedtext to "{aaa}{bbb}"
+%   * Set \fullindexsortkey to "aaa @subentry ZZZ"
+%   * If @seealso occurs, set \pagenumbertext
 %
-\def\dosubindwrite{%
-  % Put the index entry in the margin if desired.
-  \ifx\SETmarginindex\relax\else
-    \insert\margin{\hbox{\vrule height8pt depth3pt width0pt \the\toks0}}%
+\def\splitindexentry#1{%
+  \gdef\fullindexsortkey{}%
+  \xdef\bracedtext{}%
+  \def\sep{}%
+  \def\seealso##1{}%
+  \def\seeentry##1{}%
+  \expandafter\doindexsegment#1\subentry\finish\subentry
+}
+
+% append the results from the next segment
+\def\doindexsegment#1\subentry{%
+  \def\segment{#1}%
+  \ifx\segment\isfinish
+  \else
+    %
+    % Fully expand the segment, throwing away any @sortas directives, and
+    % trim spaces.
+    \edef\trimmed{\segment}%
+    \edef\trimmed{\expandafter\eatspaces\expandafter{\trimmed}}%
+    %
+    \xdef\bracedtext{\bracedtext{\trimmed}}%
+    %
+    % Get the string to sort by.  Process the segment with all
+    % font commands turned off.
+    \bgroup
+      \let\sortas\indexwritesortas
+      \let\seealso\indexwriteseealso
+      \let\seeentry\indexwriteseeentry
+      \indexnofonts
+      % The braces around the commands are recognized by texindex.
+      \def\lbracechar{{\string\indexlbrace}}%
+      \def\rbracechar{{\string\indexrbrace}}%
+      \let\{=\lbracechar
+      \let\}=\rbracechar
+      \def\@{{\string\indexatchar}}%
+      \def\atchar##1{\@}%
+      \def\backslashchar{{\string\indexbackslash}}%
+      \uccode`\~=`\\ \uppercase{\let~\backslashchar}%
+      %
+      \let\indexsortkey\empty
+      \global\let\pagenumbertext\empty
+      % Execute the segment and throw away the typeset output.  This executes
+      % any @sortas or @seealso commands in this segment.
+      \setbox\dummybox = \hbox{\segment}%
+      \ifx\indexsortkey\empty{%
+        \indexnonalnumdisappear
+        \xdef\trimmed{\segment}%
+        \xdef\trimmed{\expandafter\eatspaces\expandafter{\trimmed}}%
+        \xdef\indexsortkey{\trimmed}%
+        \ifx\indexsortkey\empty\xdef\indexsortkey{ }\fi
+      }\fi
+      %
+      % Append to \fullindexsortkey.
+      \edef\tmp{\gdef\noexpand\fullindexsortkey{%
+                  \fullindexsortkey\sep\indexsortkey}}%
+      \tmp
+    \egroup
+    \def\sep{\subentry}%
+    %
+    \expandafter\doindexsegment
+  \fi
+}
+\def\isfinish{\finish}%
+\newbox\dummybox % used above
+
+\let\subentry\relax
+
+% Use \ instead of @ in index files.  To support old texi2dvi and texindex.
+% This works without changing the escape character used in the toc or aux
+% files because the index entries are fully expanded here, and \string uses
+% the current value of \escapechar.
+\def\escapeisbackslash{\escapechar=`\\}
+
+% Use \ in index files by default.  texi2dvi didn't support @ as the escape
+% character (as it checked for "\entry" in the files, and not "@entry").  When
+% the new version of texi2dvi has had a chance to become more prevalent, then
+% the escape character can change back to @ again.  This should be an easy
+% change to make now because both @ and \ are only used as escape characters in
+% index files, never standing for themselves.
+%
+\set txiindexescapeisbackslash
+
+% Write the entry in \indextext to the index file.
+%
+\def\doindwrite{%
+  \maybemarginindex
+  %
+  \atdummies
+  %
+  \expandafter\ifx\csname SETtxiindexescapeisbackslash\endcsname\relax\else
+    \escapeisbackslash
   \fi
   %
-  % Remember, we are within a group.
-  \indexdummies % Must do this here, since \bf, etc expand at this stage
-  \useindexbackslash % \indexbackslash isn't defined now so it will be output 
-                     % as is; and it will print as backslash.
-  % The braces around \indexbrace are recognized by texindex.
-  %
-  % Get the string to sort by, by processing the index entry with all
-  % font commands turned off.
-  {\indexnofonts
-   \def\lbracechar{{\indexlbrace}}%
-   \def\rbracechar{{\indexrbrace}}%
-   \let\{=\lbracechar
-   \let\}=\rbracechar
-   \indexnonalnumdisappear
-   \xdef\indexsortkey{}%
-   \let\sortas=\indexwritesortas
-   \edef\temp{\the\toks0}%
-   \setbox\dummybox = \hbox{\temp}% Make sure to execute any \sortas
-   \ifx\indexsortkey\empty
-     \xdef\indexsortkey{\temp}%
-     \ifx\indexsortkey\empty\xdef\indexsortkey{ }\fi
-   \fi
-  }%
+  % For texindex which always views { and } as separators.
+  \def\{{\lbracechar{}}%
+  \def\}{\rbracechar{}}%
+  \uccode`\~=`\\ \uppercase{\def~{\backslashchar{}}}%
+  %
+  % Split the entry into primary entry and any subentries, and get the index
+  % sort key.
+  \splitindexentry\indextext
   %
   % Set up the complete index entry, with both the sort key and
   % the original text, including any font commands.  We write
   % three arguments to \entry to the .?? file (four in the
   % subentry case), texindex reduces to two when writing the .??s
   % sorted result.
+  %
   \edef\temp{%
     \write\writeto{%
-      \string\entry{\indexsortkey}{\noexpand\folio}{\the\toks0}}%
+      \string\entry{\fullindexsortkey}%
+        {\ifx\pagenumbertext\empty\noexpand\folio\else\pagenumbertext\fi}%
+        \bracedtext}%
   }%
   \temp
 }
-\newbox\dummybox % used above
+
+% Put the index entry in the margin if desired (undocumented).
+\def\maybemarginindex{%
+  \ifx\SETmarginindex\relax\else
+    \insert\margin{\hbox{\vrule height8pt depth3pt width0pt \relax\indextext}}%
+  \fi
+}
+\let\SETmarginindex=\relax
+
 
 % Take care of unwanted page breaks/skips around a whatsit:
 %
@@ -5462,9 +5467,14 @@ end
 %  \entry {topic}{pagelist}
 %     for a topic that is used without subtopics
 %  \primary {topic}
+%  \entry {topic}{}
 %     for the beginning of a topic that is used with subtopics
 %  \secondary {subtopic}{pagelist}
 %     for each subtopic.
+%  \secondary {subtopic}{}
+%     for a subtopic with sub-subtopics
+%  \tertiary {subtopic}{subsubtopic}{pagelist}
+%     for each sub-subtopic.
 
 % Define the user-accessible indexing commands
 % @findex, @vindex, @kindex, @cindex.
@@ -5476,11 +5486,6 @@ end
 \def\tindex {\tpindex}
 \def\pindex {\pgindex}
 
-\def\cindexsub {\begingroup\obeylines\cindexsub}
-{\obeylines %
-\gdef\cindexsub "#1" #2^^M{\endgroup %
-\dosubind{cp}{#2}{#1}}}
-
 % Define the macros used in formatting output of the sorted index material.
 
 % @printindex causes a particular index (the ??s file) to get printed.
@@ -5494,14 +5499,10 @@ end
   \plainfrenchspacing
   \everypar = {}% don't want the \kern\-parindent from indentation suppression.
   %
-  % See if the index file exists and is nonempty.
-  % Change catcode of @ here so that if the index file contains
-  % \initial {@}
-  % as its first line, TeX doesn't complain about mismatched braces
-  % (because it thinks @} is a control sequence).
-  \catcode`\@ = 12
   % See comment in \requireopenindexfile.
   \def\indexname{#1}\ifx\indexname\indexisfl\def\indexname{f1}\fi
+  %
+  % See if the index file exists and is nonempty.
   \openin 1 \jobname.\indexname s
   \ifeof 1
     % \enddoublecolumns gets confused if there is no text in the index,
@@ -5511,8 +5512,6 @@ end
     \putwordIndexNonexistent
     \typeout{No file \jobname.\indexname s.}%
   \else
-    \catcode`\\ = 0
-    %
     % If the index file exists but is empty, then \openin leaves \ifeof
     % false.  We have to make TeX try to read something from the file, so
     % it can discover if there is anything in it.
@@ -5520,47 +5519,51 @@ end
     \ifeof 1
       \putwordIndexIsEmpty
     \else
-      % Index files are almost Texinfo source, but we use \ as the escape
-      % character.  It would be better to use @, but that's too big a change
-      % to make right now.
-      \def\indexbackslash{\ttbackslash}%
-      \let\indexlbrace\{   % Likewise, set these sequences for braces
-      \let\indexrbrace\}   % used in the sort key.
-      \begindoublecolumns
-      \let\dotheinsertentrybox\dotheinsertentryboxwithpenalty
-      %
-      % Read input from the index file line by line.
-      \loopdo
-        \ifeof1 \else
-          \read 1 to \nextline
-        \fi
-        %
-        \indexinputprocessing
-        \thisline
-        %
-        \ifeof1\else
-        \let\thisline\nextline
-      \repeat
-      %%
-      \enddoublecolumns
+      \expandafter\printindexzz\thisline\relax\relax\finish%
     \fi
   \fi
   \closein 1
 \endgroup}
-\def\loopdo#1\repeat{\def\body{#1}\loopdoxxx}
-\def\loopdoxxx{\let\next=\relax\body\let\next=\loopdoxxx\fi\next}
 
-\def\indexinputprocessing{%
-  \ifeof1
-    \let\firsttoken\relax
+% If the index file starts with a backslash, forgo reading the index
+% file altogether.  If somebody upgrades texinfo.tex they may still have
+% old index files using \ as the escape character.  Reading this would
+% at best lead to typesetting garbage, at worst a TeX syntax error.
+\def\printindexzz#1#2\finish{%
+  \expandafter\ifx\csname SETtxiindexescapeisbackslash\endcsname\relax
+    \uccode`\~=`\\ \uppercase{\if\noexpand~}\noexpand#1
+      \expandafter\ifx\csname SETtxiskipindexfileswithbackslash\endcsname\relax
+\errmessage{%
+ERROR: A sorted index file in an obsolete format was skipped.
+To fix this problem, please upgrade your version of 'texi2dvi'
+or 'texi2pdf' to that at <https://ftp.gnu.org/gnu/texinfo>.
+If you are using an old version of 'texindex' (part of the Texinfo
+distribution), you may also need to upgrade to a newer version (at least 6.0).
+You may be able to typeset the index if you run
+'texindex \jobname.\indexname' yourself.
+You could also try setting the 'txiindexescapeisbackslash' flag by
+running a command like
+'texi2dvi -t "@set txiindexescapeisbackslash" \jobname.texi'.  If you do
+this, Texinfo will try to use index files in the old format.
+If you continue to have problems, deleting the index files and starting again
+might help (with 'rm \jobname.?? \jobname.??s')%
+}%
+      \else
+        (Skipped sorted index file in obsolete format)
+      \fi
+    \else
+      \begindoublecolumns
+      \input \jobname.\indexname s
+      \enddoublecolumns
+    \fi
   \else
-    \edef\act{\gdef\noexpand\firsttoken{\getfirsttoken\nextline}}%
-    \act
+    \begindoublecolumns
+    \catcode`\\=0\relax
+    \catcode`\@=12\relax
+    \input \jobname.\indexname s
+    \enddoublecolumns
   \fi
 }
-\def\getfirsttoken#1{\expandafter\getfirsttokenx#1\endfirsttoken}
-\long\def\getfirsttokenx#1#2\endfirsttoken{\noexpand#1}
-
 
 % These macros are used by the sorted index file itself.
 % Change them to control the appearance of the index.
@@ -5569,12 +5572,19 @@ end
 \catcode`\|=13 \catcode`\<=13 \catcode`\>=13 \catcode`\+=13 \catcode`\"=13
 \catcode`\$=3
 \gdef\initialglyphs{%
+  % special control sequences used in the index sort key
+  \let\indexlbrace\{%
+  \let\indexrbrace\}%
+  \let\indexatchar\@%
+  \def\indexbackslash{\math{\backslash}}%
+  %
   % Some changes for non-alphabetic characters.  Using the glyphs from the
   % math fonts looks more consistent than the typewriter font used elsewhere
   % for these characters.
-  \def\indexbackslash{\math{\backslash}}%
-  \let\\=\indexbackslash
+  \uccode`\~=`\\ \uppercase{\def~{\math{\backslash}}}
   %
+  % In case @\ is used for backslash
+  \uppercase{\let\\=~}
   % Can't get bold backslash so don't use bold forward slash
   \catcode`\/=13
   \def/{{\secrmnotbold \normalslash}}%
@@ -5604,7 +5614,7 @@ end
   % bottom of a column to reduce an increase in inter-line spacing.
   \nobreak
   \vskip 0pt plus 5\baselineskip
-  \penalty -300 
+  \penalty -300
   \vskip 0pt plus -5\baselineskip
   %
   % Typeset the initial.  Making this add up to a whole number of
@@ -5634,12 +5644,6 @@ end
 \def\entry{%
   \begingroup
     %
-    % For pdfTeX and XeTeX.
-    % The redefinition of \domark stops marks being added in \pdflink to 
-    % preserve coloured links across page boundaries.  Otherwise the marks
-    % would get in the way of \lastbox in \insertentrybox.
-    \let\domark\relax
-    %
     % Start a new paragraph if necessary, so our assignments below can't
     % affect previous text.
     \par
@@ -5672,35 +5676,31 @@ end
 \gdef\finishentry#1{%
     \egroup % end box A
     \dimen@ = \wd\boxA % Length of text of entry
-    \global\setbox\boxA=\hbox\bgroup\unhbox\boxA
-    % #1 is the page number.
-    %
-    % Get the width of the page numbers, and only use
-    % leaders if they are present.
-    \global\setbox\boxB = \hbox{#1}%
-    \ifdim\wd\boxB = 0pt
-      \null\nobreak\hfill\ %
-    \else
-      %
-      \null\nobreak\indexdotfill % Have leaders before the page number.
+    \global\setbox\boxA=\hbox\bgroup
+      \unhbox\boxA
+      % #1 is the page number.
       %
-      \ifpdf
-        \pdfgettoks#1.%
-        \hskip\skip\thinshrinkable\the\toksA
+      % Get the width of the page numbers, and only use
+      % leaders if they are present.
+      \global\setbox\boxB = \hbox{#1}%
+      \ifdim\wd\boxB = 0pt
+        \null\nobreak\hfill\ %
       \else
-        \ifx\XeTeXrevision\thisisundefined
-          \hskip\skip\thinshrinkable #1%
-        \else
+        %
+        \null\nobreak\indexdotfill % Have leaders before the page number.
+        %
+        \ifpdforxetex
           \pdfgettoks#1.%
           \hskip\skip\thinshrinkable\the\toksA
+        \else
+          \hskip\skip\thinshrinkable #1%
         \fi
       \fi
-    \fi
     \egroup % end \boxA
     \ifdim\wd\boxB = 0pt
-      \global\setbox\entrybox=\vbox{\unhbox\boxA}%
-    \else
-    \global\setbox\entrybox=\vbox\bgroup
+      \noindent\unhbox\boxA\par
+      \nobreak
+    \else\bgroup
       % We want the text of the entries to be aligned to the left, and the
       % page numbers to be aligned to the right.
       %
@@ -5730,7 +5730,7 @@ end
       \advance\dimen@ii by 1\dimen@i
       \ifdim\wd\boxA > \dimen@ii % If the entry doesn't fit in one line
       \ifdim\dimen@ > 0.8\dimen@ii   % due to long index text
-        % Try to split the text roughly evenly.  \dimen@ will be the length of 
+        % Try to split the text roughly evenly.  \dimen@ will be the length of
         % the first line.
         \dimen@ = 0.7\dimen@
         \dimen@ii = \hsize
@@ -5766,55 +5766,11 @@ end
     \egroup % The \vbox
     \fi
   \endgroup
-  \dotheinsertentrybox
 }}
 
 \newskip\thinshrinkable
 \skip\thinshrinkable=.15em minus .15em
 
-\newbox\entrybox
-\def\insertentrybox{%
-  \ourunvbox\entrybox
-}
-
-% default definition
-\let\dotheinsertentrybox\insertentrybox
-
-% Use \lastbox to take apart vbox box by box, and add each sub-box
-% to the current vertical list.
-\def\ourunvbox#1{%
-\bgroup % for local binding of \delayedbox
-  % Remove the last box from box #1
-  \global\setbox#1=\vbox{%
-    \unvbox#1%
-    \unskip % remove any glue
-    \unpenalty
-    \global\setbox\interbox=\lastbox
-  }%
-  \setbox\delayedbox=\box\interbox
-  \ifdim\ht#1=0pt\else
-    \ourunvbox#1 % Repeat on what's left of the box
-    \nobreak
-  \fi
-  \box\delayedbox
-\egroup
-}
-\newbox\delayedbox
-\newbox\interbox
-
-% Used from \printindex.  \firsttoken should be the first token
-% after the \entry.  If it's not another \entry, we are at the last
-% line of a group of index entries, so insert a penalty to discourage
-% widowed index entries.
-\def\dotheinsertentryboxwithpenalty{%
-  \ifx\firsttoken\isentry
-  \else
-    \penalty 9000
-  \fi
-  \insertentrybox
-}
-\def\isentry{\entry}%
-
 % Like plain.tex's \dotfill, except uses up at least 1 em.
 % The filll stretch here overpowers both the fil and fill stretch to push
 % the page number to the right.
@@ -5824,24 +5780,15 @@ end
 
 \def\primary #1{\line{#1\hfil}}
 
-\newskip\secondaryindent \secondaryindent=0.5cm
-\def\secondary#1#2{{%
-  \parfillskip=0in
-  \parskip=0in
-  \hangindent=1in
-  \hangafter=1
-  \noindent\hskip\secondaryindent\hbox{#1}\indexdotfill
-  \ifpdf
-    \pdfgettoks#2.\ \the\toksA % The page number ends the paragraph.
-  \else
-    \ifx\XeTeXrevision\thisisundefined
-      #2
-    \else
-      \pdfgettoks#2.\ \the\toksA % The page number ends the paragraph.
-    \fi
-  \fi
-  \par
-}}
+\def\secondary{\indententry{0.5cm}}
+\def\tertiary{\indententry{1cm}}
+
+\def\indententry#1#2#3{%
+  \bgroup
+  \leftskip=#1
+  \entry{#2}{#3}%
+  \egroup
+}
 
 % Define two-column mode, which we use to typeset indexes.
 % Adapted from the TeXbook, page 416, which is to say,
@@ -5851,60 +5798,21 @@ end
 \newbox\partialpage
 \newdimen\doublecolumnhsize
 
-% Use inside an output routine to save \topmark and \firstmark
-\def\savemarks{%
-  \global\savedtopmark=\expandafter{\topmark }%
-  \global\savedfirstmark=\expandafter{\firstmark }%
-}
-\newtoks\savedtopmark
-\newtoks\savedfirstmark
-
-% Set \topmark and \firstmark for next time \output runs.
-% Can't be run from withinside \output (because any material
-% added while an output routine is active, including 
-% penalties, is saved for after it finishes).  The page so far
-% should be empty, otherwise what's on it will be thrown away.
-\def\restoremarks{%
-  \mark{\the\savedtopmark}%
-  \bgroup\output = {%
-    \setbox\dummybox=\box\PAGE
-  }abc\eject\egroup
-  % "abc" because output routine doesn't fire for a completely empty page.
-  \mark{\the\savedfirstmark}%
-}
-
 \def\begindoublecolumns{\begingroup % ended by \enddoublecolumns
   % If not much space left on page, start a new page.
   \ifdim\pagetotal>0.8\vsize\vfill\eject\fi
   %
   % Grab any single-column material above us.
   \output = {%
-    %
-    % Here is a possibility not foreseen in manmac: if we accumulate a
-    % whole lot of material, we might end up calling this \output
-    % routine twice in a row (see the doublecol-lose test, which is
-    % essentially a couple of indexes with @setchapternewpage off).  In
-    % that case we just ship out what is in \partialpage with the normal
-    % output routine.  Generally, \partialpage will be empty when this
-    % runs and this will be a no-op.  See the indexspread.tex test case.
-    \ifvoid\partialpage \else
-      \onepageout{\pagecontents\partialpage}%
-    \fi
+    \savetopmark
     %
     \global\setbox\partialpage = \vbox{%
       % Unvbox the main output page.
       \unvbox\PAGE
       \kern-\topskip \kern\baselineskip
     }%
-    \savemarks
   }%
   \eject % run that output routine to set \partialpage
-  \restoremarks
-  %
-  % We recover the two marks that the last output routine saved in order
-  % to propagate the information in marks added around a chapter heading,
-  % which could be otherwise be lost by the time the final page is output.
-  %
   %
   % Use the double-column output routine for subsequent pages.
   \output = {\doublecolumnout}%
@@ -5930,7 +5838,9 @@ end
     \divide\doublecolumnhsize by 2
   \hsize = \doublecolumnhsize
   %
-  % Double the \vsize as well.
+  % Get the available space for the double columns -- the normal
+  % (undoubled) page height minus any material left over from the
+  % previous page.
   \advance\vsize by -\ht\partialpage
   \vsize = 2\vsize
   %
@@ -5943,17 +5853,15 @@ end
 %
 \def\doublecolumnout{%
   %
+  \savetopmark
   \splittopskip=\topskip \splitmaxdepth=\maxdepth
-  % Get the available space for the double columns -- the normal
-  % (undoubled) page height minus any material left over from the
-  % previous page.
   \dimen@ = \vsize
   \divide\dimen@ by 2
   %
   % box0 will be the left-hand column, box2 the right.
   \setbox0=\vsplit\PAGE to\dimen@ \setbox2=\vsplit\PAGE to\dimen@
   \global\advance\vsize by 2\ht\partialpage
-  \onepageout\pagesofar
+  \onepageout\pagesofar % empty except for the first time we are called
   \unvbox\PAGE
   \penalty\outputpenalty
 }
@@ -5969,7 +5877,7 @@ end
 }
 
 
-% Finished with with double columns.
+% Finished with double columns.
 \def\enddoublecolumns{%
   % The following penalty ensures that the page builder is exercised
   % _before_ we change the output routine.  This is necessary in the
@@ -6001,7 +5909,7 @@ end
   %
   \output = {%
     % Split the last of the double-column material.
-    \savemarks
+    \savetopmark
     \balancecolumns
   }%
   \eject % call the \output just set
@@ -6009,10 +5917,9 @@ end
     % Having called \balancecolumns once, we do not
     % want to call it again.  Therefore, reset \output to its normal
     % definition right away.
-    \global\output = {\onepageout{\pagecontents\PAGE}}%
+    \global\output=\expandafter{\the\defaultoutput}
     %
     \endgroup % started in \begindoublecolumns
-    \restoremarks
     % Leave the double-column material on the current page, no automatic
     % page break.
     \box\balancedcolumns
@@ -6031,18 +5938,19 @@ end
 \newbox\balancedcolumns
 \setbox\balancedcolumns=\vbox{shouldnt see this}%
 %
-% Only called for the last of the double column material.  \doublecolumnout 
+% Only called for the last of the double column material.  \doublecolumnout
 % does the others.
 \def\balancecolumns{%
   \setbox0 = \vbox{\unvbox\PAGE}% like \box255 but more efficient, see p.120.
   \dimen@ = \ht0
-  \advance\dimen@ by \topskip
-  \advance\dimen@ by-\baselineskip
-  \ifdim\dimen@<5\baselineskip
+  \ifdim\dimen@<7\baselineskip
     % Don't split a short final column in two.
     \setbox2=\vbox{}%
     \global\setbox\balancedcolumns=\vbox{\pagesofar}%
   \else
+    % double the leading vertical space
+    \advance\dimen@ by \topskip
+    \advance\dimen@ by-\baselineskip
     \divide\dimen@ by 2 % target to split to
     \dimen@ii = \dimen@
     \splittopskip = \topskip
@@ -6058,7 +5966,7 @@ end
     }%
     % Now the left column is in box 1, and the right column in box 3.
     %
-    % Check whether the left column has come out higher than the page itself.  
+    % Check whether the left column has come out higher than the page itself.
     % (Note that we have doubled \vsize for the double columns, so
     % the actual height of the page is 0.5\vsize).
     \ifdim2\ht1>\vsize
@@ -6177,11 +6085,9 @@ end
 
 % @raisesections: treat @section as chapter, @subsection as section, etc.
 \def\raisesections{\global\advance\secbase by -1}
-\let\up=\raisesections % original BFox name
 
 % @lowersections: treat @chapter as section, @section as subsection, etc.
 \def\lowersections{\global\advance\secbase by 1}
-\let\down=\lowersections % original BFox name
 
 % we only have subsub.
 \chardef\maxseclevel = 3
@@ -6357,7 +6263,7 @@ end
 \let\top\unnumbered
 
 % Sections.
-% 
+%
 \outer\parseargdef\numberedsec{\numhead1{#1}} % normally calls seczzz
 \def\seczzz#1{%
   \global\subsecno=0 \global\subsubsecno=0  \global\advance\secno by 1
@@ -6380,7 +6286,7 @@ end
 }
 
 % Subsections.
-% 
+%
 % normally calls numberedsubseczzz:
 \outer\parseargdef\numberedsubsec{\numhead2{#1}}
 \def\numberedsubseczzz#1{%
@@ -6405,7 +6311,7 @@ end
 }
 
 % Subsubsections.
-% 
+%
 % normally numberedsubsubseczzz:
 \outer\parseargdef\numberedsubsubsec{\numhead3{#1}}
 \def\numberedsubsubseczzz#1{%
@@ -6526,27 +6432,22 @@ end
   \expandafter\ifx\thisenv\titlepage\else
     \checkenv{}% chapters, etc., should not start inside an environment.
   \fi
-  % FIXME: \chapmacro is currently called from inside \titlepage when
-  % \setcontentsaftertitlepage to print the "Table of Contents" heading, but
-  % this should probably be done by \sectionheading with an option to print
-  % in chapter size.
-  %
   % Insert the first mark before the heading break (see notes for \domark).
-  \let\prevchapterdefs=\lastchapterdefs
-  \let\prevsectiondefs=\lastsectiondefs
-  \gdef\lastsectiondefs{\gdef\thissectionname{}\gdef\thissectionnum{}%
+  \let\prevchapterdefs=\currentchapterdefs
+  \let\prevsectiondefs=\currentsectiondefs
+  \gdef\currentsectiondefs{\gdef\thissectionname{}\gdef\thissectionnum{}%
                         \gdef\thissection{}}%
   %
   \def\temptype{#2}%
   \ifx\temptype\Ynothingkeyword
-    \gdef\lastchapterdefs{\gdef\thischaptername{#1}\gdef\thischapternum{}%
+    \gdef\currentchapterdefs{\gdef\thischaptername{#1}\gdef\thischapternum{}%
                           \gdef\thischapter{\thischaptername}}%
   \else\ifx\temptype\Yomitfromtockeyword
-    \gdef\lastchapterdefs{\gdef\thischaptername{#1}\gdef\thischapternum{}%
+    \gdef\currentchapterdefs{\gdef\thischaptername{#1}\gdef\thischapternum{}%
                           \gdef\thischapter{}}%
   \else\ifx\temptype\Yappendixkeyword
     \toks0={#1}%
-    \xdef\lastchapterdefs{%
+    \xdef\currentchapterdefs{%
       \gdef\noexpand\thischaptername{\the\toks0}%
       \gdef\noexpand\thischapternum{\appendixletter}%
       % \noexpand\putwordAppendix avoids expanding indigestible
@@ -6557,7 +6458,7 @@ end
     }%
   \else
     \toks0={#1}%
-    \xdef\lastchapterdefs{%
+    \xdef\currentchapterdefs{%
       \gdef\noexpand\thischaptername{\the\toks0}%
       \gdef\noexpand\thischapternum{\the\chapno}%
       % \noexpand\putwordChapter avoids expanding indigestible
@@ -6577,18 +6478,18 @@ end
   %
   % Now the second mark, after the heading break.  No break points
   % between here and the heading.
-  \let\prevchapterdefs=\lastchapterdefs
-  \let\prevsectiondefs=\lastsectiondefs
+  \let\prevchapterdefs=\currentchapterdefs
+  \let\prevsectiondefs=\currentsectiondefs
   \domark
   %
   {%
     \chapfonts \rm
     \let\footnote=\errfootnoteheading % give better error message
     %
-    % Have to define \lastsection before calling \donoderef, because the
+    % Have to define \currentsection before calling \donoderef, because the
     % xref code eventually uses it.  On the other hand, it has to be called
     % after \pchapsepmacro, or the headline will change too soon.
-    \gdef\lastsection{#1}%
+    \gdef\currentsection{#1}%
     %
     % Only insert the separating space if we have a chapter/appendix
     % number, and don't print the unnumbered ``number''.
@@ -6677,10 +6578,10 @@ end
     \csname #2fonts\endcsname \rm
     %
     % Insert first mark before the heading break (see notes for \domark).
-    \let\prevsectiondefs=\lastsectiondefs
+    \let\prevsectiondefs=\currentsectiondefs
     \ifx\temptype\Ynothingkeyword
       \ifx\sectionlevel\seckeyword
-        \gdef\lastsectiondefs{\gdef\thissectionname{#1}\gdef\thissectionnum{}%
+        \gdef\currentsectiondefs{\gdef\thissectionname{#1}\gdef\thissectionnum{}%
                               \gdef\thissection{\thissectionname}}%
       \fi
     \else\ifx\temptype\Yomitfromtockeyword
@@ -6688,7 +6589,7 @@ end
     \else\ifx\temptype\Yappendixkeyword
       \ifx\sectionlevel\seckeyword
         \toks0={#1}%
-        \xdef\lastsectiondefs{%
+        \xdef\currentsectiondefs{%
           \gdef\noexpand\thissectionname{\the\toks0}%
           \gdef\noexpand\thissectionnum{#4}%
           % \noexpand\putwordSection avoids expanding indigestible
@@ -6701,7 +6602,7 @@ end
     \else
       \ifx\sectionlevel\seckeyword
         \toks0={#1}%
-        \xdef\lastsectiondefs{%
+        \xdef\currentsectiondefs{%
           \gdef\noexpand\thissectionname{\the\toks0}%
           \gdef\noexpand\thissectionnum{#4}%
           % \noexpand\putwordSection avoids expanding indigestible
@@ -6727,28 +6628,28 @@ end
     %
     % Now the second mark, after the heading break.  No break points
     % between here and the heading.
-    \global\let\prevsectiondefs=\lastsectiondefs
+    \global\let\prevsectiondefs=\currentsectiondefs
     \domark
     %
     % Only insert the space after the number if we have a section number.
     \ifx\temptype\Ynothingkeyword
       \setbox0 = \hbox{}%
       \def\toctype{unn}%
-      \gdef\lastsection{#1}%
+      \gdef\currentsection{#1}%
     \else\ifx\temptype\Yomitfromtockeyword
       % for @headings -- no section number, don't include in toc,
-      % and don't redefine \lastsection.
+      % and don't redefine \currentsection.
       \setbox0 = \hbox{}%
       \def\toctype{omit}%
       \let\sectionlevel=\empty
     \else\ifx\temptype\Yappendixkeyword
       \setbox0 = \hbox{#4\enspace}%
       \def\toctype{app}%
-      \gdef\lastsection{#1}%
+      \gdef\currentsection{#1}%
     \else
       \setbox0 = \hbox{#4\enspace}%
       \def\toctype{num}%
-      \gdef\lastsection{#1}%
+      \gdef\currentsection{#1}%
     \fi\fi\fi
     %
     % Write the toc entry (before \donoderef).  See comments in \chapmacro.
@@ -6838,13 +6739,8 @@ end
   % 1 and 2 (the page numbers aren't printed), and so are the first
   % two pages of the document.  Thus, we'd have two destinations named
   % `1', and two named `2'.
-  \ifpdf
+  \ifpdforxetex
     \global\pdfmakepagedesttrue
-  \else
-    \ifx\XeTeXrevision\thisisundefined
-    \else
-      \global\pdfmakepagedesttrue
-    \fi
   \fi
 }
 
@@ -7207,11 +7103,7 @@ end
 
 % @cartouche ... @end cartouche: draw rectangle w/rounded corners around
 % environment contents.
-\font\circle=lcircle10
-\newdimen\circthick
-\newdimen\cartouter\newdimen\cartinner
-\newskip\normbskip\newskip\normpskip\newskip\normlskip
-\circthick=\fontdimen8\circle
+
 %
 \def\ctl{{\circle\char'013\hskip -6pt}}% 6pt from pl file: 1/2charwidth
 \def\ctr{{\hskip 6pt\circle\char'010}}
@@ -7226,7 +7118,18 @@ end
 %
 \newskip\lskip\newskip\rskip
 
+% only require the font if @cartouche is actually used
+\def\cartouchefontdefs{%
+  \font\circle=lcircle10\relax
+  \circthick=\fontdimen8\circle
+}
+\newdimen\circthick
+\newdimen\cartouter\newdimen\cartinner
+\newskip\normbskip\newskip\normpskip\newskip\normlskip
+
+
 \envdef\cartouche{%
+  \cartouchefontdefs
   \ifhmode\par\fi  % can't be in the midst of a paragraph.
   \startsavinginserts
   \lskip=\leftskip \rskip=\rightskip
@@ -7405,13 +7308,9 @@ end
 
 
 % @raggedright does more-or-less normal line breaking but no right
-% justification.  From plain.tex.  Don't stretch around special
-% characters in urls in this environment, since the stretch at the right
-% should be enough.
+% justification.  From plain.tex.
 \envdef\raggedright{%
   \rightskip0pt plus2.4em \spaceskip.3333em \xspaceskip.5em\relax
-  \def\urefprestretchamount{0pt}%
-  \def\urefpoststretchamount{0pt}%
 }
 \let\Eraggedright\par
 
@@ -7470,7 +7369,7 @@ end
 
 % @indentedblock is like @quotation, but indents only on the left and
 % has no optional argument.
-% 
+%
 \makedispenvdef{indentedblock}{\indentedblockstart}
 %
 \def\indentedblockstart{%
@@ -7573,7 +7472,7 @@ end
   \nonfillstart
   \tt % easiest (and conventionally used) font for verbatim
   % The \leavevmode here is for blank lines.  Otherwise, we would
-  % never \starttabox and the \egroup would end verbatim mode.
+  % never \starttabbox and the \egroup would end verbatim mode.
   \def\par{\leavevmode\egroup\box\verbbox\endgraf}%
   \tabexpand
   \setupmarkupstyle{verbatim}%
@@ -7636,9 +7535,12 @@ end
   {%
     \makevalueexpandable
     \setupverbatim
-    \indexnofonts       % Allow `@@' and other weird things in file names.
-    \wlog{texinfo.tex: doing @verbatiminclude of #1^^J}%
-    \input #1
+    {%
+      \indexnofonts       % Allow `@@' and other weird things in file names.
+      \wlog{texinfo.tex: doing @verbatiminclude of #1^^J}%
+      \edef\tmp{\noexpand\input #1 }
+      \expandafter
+    }\tmp
     \afterenvbreak
   }%
 }
@@ -7767,7 +7669,7 @@ end
 % @deftypefnnewline on|off says whether the return type of typed functions
 % are printed on their own line.  This affects @deftypefn, @deftypefun,
 % @deftypeop, and @deftypemethod.
-% 
+%
 \parseargdef\deftypefnnewline{%
   \def\temp{#1}%
   \ifx\temp\onword
@@ -7783,6 +7685,21 @@ end
   \fi\fi
 }
 
+% \dosubind {index}{topic}{subtopic}
+%
+% If SUBTOPIC is present, precede it with a space, and call \doind.
+% (At some time during the 20th century, this made a two-level entry in an
+% index such as the operation index.  Nobody seemed to notice the change in
+% behaviour though.)
+\def\dosubind#1#2#3{%
+  \def\thirdarg{#3}%
+  \ifx\thirdarg\empty
+    \doind{#1}{#2}%
+  \else
+    \doind{#1}{#2\space#3}%
+  \fi
+}
+
 % Untyped functions:
 
 % @deffn category name args
@@ -7797,7 +7714,6 @@ end
 % \deffngeneral {subind}category name args
 %
 \def\deffngeneral#1#2 #3 #4\endheader{%
-  % Remember that \dosubind{fn}{foo}{} is equivalent to \doind{fn}{foo}.
   \dosubind{fn}{\code{#3}}{#1}%
   \defname{#2}{}{#3}\magicamp\defunargs{#4\unskip}%
 }
@@ -7948,7 +7864,7 @@ end
       \tclose{\temp}% typeset the return type
       \ifrettypeownline
         % put return type on its own line; prohibit line break following:
-        \hfil\vadjust{\nobreak}\break  
+        \hfil\vadjust{\nobreak}\break
       \else
         \space  % type on same line, so just followed by a space
       \fi
@@ -8085,36 +8001,18 @@ end
   }
 \fi
 
-% alias because \c means cedilla in @tex or @math
-\let\texinfoc=\c
-
-\newcount\savedcatcodeone
-\newcount\savedcatcodetwo
-
 % Used at the time of macro expansion.
 % Argument is macro body with arguments substituted
 \def\scanmacro#1{%
   \newlinechar`\^^M
   \def\xeatspaces{\eatspaces}%
   %
-  % Temporarily undo catcode changes of \printindex.  Set catcode of @ to
-  % 0 so that @-commands in macro expansions aren't printed literally when 
-  % formatting an index file, where \ is used as the escape character.
-  \savedcatcodeone=\catcode`\@
-  \savedcatcodetwo=\catcode`\\
-  \catcode`\@=0
-  \catcode`\\=\active
-  %
   % Process the macro body under the current catcode regime.
-  \scantokens{#1@texinfoc}%
-  %
-  \catcode`\@=\savedcatcodeone
-  \catcode`\\=\savedcatcodetwo
+  \scantokens{#1@comment}%
   %
-  % The \texinfoc is to remove the \newlinechar added by \scantokens, and
-  % can be noticed by \parsearg.
-  %   We avoid surrounding the call to \scantokens with \bgroup and \egroup
-  % to allow macros to open or close groups themselves.
+  % The \comment is to remove the \newlinechar added by \scantokens, and
+  % can be noticed by \parsearg.  Note \c isn't used because this means cedilla
+  % in math mode.
 }
 
 % Used for copying and captions
@@ -8215,12 +8113,14 @@ end
 \def\macroargctxt{%
   \scanctxt
   \catcode`\ =\active
+  \catcode`\@=\other
   \catcode`\^^M=\other
   \catcode`\\=\active
 }
 
 \def\macrolineargctxt{% used for whole-line arguments without braces
   \scanctxt
+  \catcode`\@=\other
   \catcode`\{=\other
   \catcode`\}=\other
 }
@@ -8312,7 +8212,7 @@ end
 % list to some hook where the argument is to be expanded.  If there are
 % less than 10 arguments that hook is to be replaced by ##N where N
 % is the position in that list, that is to say the macro arguments are to be
-% defined `a la TeX in the macro body.  
+% defined `a la TeX in the macro body.
 %
 % That gets used by \mbodybackslash (above).
 %
@@ -8343,8 +8243,8 @@ end
 %
 % Read recursive and nonrecursive macro bodies. (They're different since
 % rec and nonrec macros end differently.)
-% 
-% We are in \macrobodyctxt, and the \xdef causes backslashshes in the macro 
+%
+% We are in \macrobodyctxt, and the \xdef causes backslashshes in the macro
 % body to be transformed.
 % Set \macrobody to the body of the macro, and call \defmacro.
 %
@@ -8378,7 +8278,7 @@ end
 % twice the \macarg.BLAH macros does not cost too much processing power.
 \def\parsemmanyargdef@@#1,{%
   \if#1;\let\next=\relax
-  \else 
+  \else
     \let\next=\parsemmanyargdef@@
     \edef\tempb{\eatspaces{#1}}%
     \expandafter\def\expandafter\tempa
@@ -8463,7 +8363,7 @@ end
 
 % Replace arguments by their values in the macro body, and place the result
 % in macro \@tempa.
-% 
+%
 \def\macvalstoargs@{%
   %  To do this we use the property that token registers that are \the'ed
   % within an \edef  expand only once. So we are going to place all argument
@@ -8487,9 +8387,9 @@ end
   \expandafter\def\expandafter\@tempa\expandafter{\@tempc}%
   }
 
-% Define the named-macro outside of this group and then close this group. 
-% 
-\def\macargexpandinbody@{% 
+% Define the named-macro outside of this group and then close this group.
+%
+\def\macargexpandinbody@{%
   \expandafter
   \endgroup
   \macargdeflist@
@@ -8527,7 +8427,7 @@ end
 }
 
 % Trailing missing arguments are set to empty.
-% 
+%
 \def\setemptyargvalues@{%
   \ifx\paramlist\nilm@
     \let\next\macargexpandinbody@
@@ -8604,7 +8504,7 @@ end
   \else % at most 9
     \ifnum\paramno<10\relax
       % @MACNAME sets the context for reading the macro argument
-      % @MACNAME@@ gets the argument, processes backslashes and appends a 
+      % @MACNAME@@ gets the argument, processes backslashes and appends a
       % comma.
       % @MACNAME@@@ removes braces surrounding the argument list.
       % @MACNAME@@@@ scans the macro body with arguments substituted.
@@ -8648,11 +8548,11 @@ end
 % Call #1 with a list of tokens #2, with any doubled backslashes in #2
 % compressed to one.
 %
-% This implementation works by expansion, and not execution (so we cannot use 
-% \def or similar).  This reduces the risk of this failing in contexts where 
-% complete expansion is done with no execution (for example, in writing out to 
+% This implementation works by expansion, and not execution (so we cannot use
+% \def or similar).  This reduces the risk of this failing in contexts where
+% complete expansion is done with no execution (for example, in writing out to
 % an auxiliary file for an index entry).
-% 
+%
 % State is kept in the input stream: the argument passed to
 % @look_ahead, @gobble_and_check_finish and @add_segment is
 %
@@ -8674,11 +8574,11 @@ end
 % #3 - NEXT_TOKEN
 % #4 used to look ahead
 %
-% If the next token is not a backslash, process the rest of the argument; 
+% If the next token is not a backslash, process the rest of the argument;
 % otherwise, remove the next token.
 @gdef@look_ahead#1!#2#3#4{%
   @ifx#4\%
-   @expandafter@gobble_and_check_finish 
+   @expandafter@gobble_and_check_finish
   @else
    @expandafter@add_segment
   @fi#1!{#2}#4#4%
@@ -8702,9 +8602,9 @@ end
 % #3 - NEXT_TOKEN
 % #4 is input stream until next backslash
 %
-% Input stream is either at the start of the argument, or just after a 
-% backslash sequence, either a lone backslash, or a doubled backslash.  
-% NEXT_TOKEN contains the first token in the input stream: if it is \finish, 
+% Input stream is either at the start of the argument, or just after a
+% backslash sequence, either a lone backslash, or a doubled backslash.
+% NEXT_TOKEN contains the first token in the input stream: if it is \finish,
 % finish; otherwise, append to ARG_RESULT the segment of the argument up until
 % the next backslash.  PENDING_BACKSLASH contains a backslash to represent
 % a backslash just before the start of the input stream that has not been
@@ -8716,13 +8616,13 @@ end
   % append the pending backslash to the result, followed by the next segment
   @expandafter@is_fi@look_ahead#1#2#4!{\}@fi
   % this @fi is discarded by @look_ahead.
-  % we can't get rid of it with \expandafter because we don't know how 
+  % we can't get rid of it with \expandafter because we don't know how
   % long #4 is.
 }
 
 % #1 - THE_MACRO
 % #2 - ARG_RESULT
-% #3 discards the res of the conditional in @add_segment, and @is_fi ends the 
+% #3 discards the res of the conditional in @add_segment, and @is_fi ends the
 % conditional.
 @gdef@call_the_macro#1#2!#3@fi{@is_fi #1{#2}}
 
@@ -8734,7 +8634,7 @@ end
 % for reading the argument (slightly different in the two cases).  Then,
 % to read the argument, in the whole-line case, it then calls the regular
 % \parsearg MAC; in the lbrace case, it calls \passargtomacro MAC.
-% 
+%
 \def\braceorline#1{\let\macnamexxx=#1\futurelet\nchar\braceorlinexxx}
 \def\braceorlinexxx{%
   \ifx\nchar\bgroup
@@ -8784,9 +8684,29 @@ end
 % also remove a trailing comma, in case of something like this:
 % @node Help-Cross,  ,  , Cross-refs
 \def\donode#1 ,#2\finishnodeparse{\dodonode #1,\finishnodeparse}
-\def\dodonode#1,#2\finishnodeparse{\gdef\lastnode{#1}}
+\def\dodonode#1,#2\finishnodeparse{\gdef\lastnode{#1}\omittopnode}
+
+% Used so that the @top node doesn't have to be wrapped in an @ifnottex
+% conditional.
+% \doignore goes to more effort to skip nested conditionals but we don't need
+% that here.
+\def\omittopnode{%
+   \ifx\lastnode\wordTop
+   \expandafter\ignorenode\fi
+}
+\def\wordTop{Top}
+
+% Until the next @node or @bye command, divert output to a box that is not
+% output.
+\def\ignorenode{\setbox\dummybox\vbox\bgroup\def\node{\egroup\node}%
+\ignorenodebye
+}
+
+{\let\bye\relax
+\gdef\ignorenodebye{\let\bye\ignorenodebyedef}
+\gdef\ignorenodebyedef{\egroup(`Top' node ignored)\bye}}
+% The redefinition of \bye here is because it is declared \outer
 
-\let\nwnode=\node
 \let\lastnode=\empty
 
 % Write a cross-reference definition for the current node.  #1 is the
@@ -8809,7 +8729,7 @@ end
 
 % \setref{NAME}{SNT} defines a cross-reference point NAME (a node or an
 % anchor), which consists of three parts:
-% 1) NAME-title - the current sectioning name taken from \lastsection,
+% 1) NAME-title - the current sectioning name taken from \currentsection,
 %                 or the anchor name.
 % 2) NAME-snt   - section number and type, passed as the SNT arg, or
 %                 empty for anchors.
@@ -8831,7 +8751,7 @@ end
 	\write\auxfile{@xrdef{#1-% #1 of \setref, expanded by the \edef
 	  ##1}{##2}}% these are parameters of \writexrdef
       }%
-      \toks0 = \expandafter{\lastsection}%
+      \toks0 = \expandafter{\currentsection}%
       \immediate \writexrdef{title}{\the\toks0 }%
       \immediate \writexrdef{snt}{\csname #2\endcsname}% \Ynumbered etc.
       \safewhatsit{\writexrdef{pg}{\folio}}% will be written later, at \shipout
@@ -8843,7 +8763,7 @@ end
 % automatically in xrefs, if the third arg is not explicitly specified.
 % This was provided as a "secret" @set xref-automatic-section-title
 % variable, now it's official.
-% 
+%
 \parseargdef\xrefautomaticsectiontitle{%
   \def\temp{#1}%
   \ifx\temp\onword
@@ -8859,7 +8779,7 @@ end
   \fi\fi
 }
 
-% 
+%
 % @xref, @pxref, and @ref generate cross-references.  For \xrefX, #1 is
 % the node name, #2 the name of the Info cross-reference, #3 the printed
 % node name, #4 the name of the Info file, #5 the name of the printed
@@ -9012,24 +8932,24 @@ end
     \fi
   \else
     % node/anchor (non-float) references.
-    % 
+    %
     % If we use \unhbox to print the node names, TeX does not insert
     % empty discretionaries after hyphens, which means that it will not
     % find a line break at a hyphen in a node names.  Since some manuals
     % are best written with fairly long node names, containing hyphens,
     % this is a loss.  Therefore, we give the text of the node name
     % again, so it is as if TeX is seeing it for the first time.
-    % 
+    %
     \ifdim \wd\printedmanualbox > 0pt
       % Cross-manual reference with a printed manual name.
-      % 
+      %
       \crossmanualxref{\cite{\printedmanual\unskip}}%
     %
     \else\ifdim \wd\infofilenamebox > 0pt
       % Cross-manual reference with only an info filename (arg 4), no
       % printed manual name (arg 5).  This is essentially the same as
       % the case above; we output the filename, since we have nothing else.
-      % 
+      %
       \crossmanualxref{\code{\infofilename\unskip}}%
     %
     \else
@@ -9069,20 +8989,20 @@ end
 \endgroup}
 
 % Output a cross-manual xref to #1.  Used just above (twice).
-% 
+%
 % Only include the text "Section ``foo'' in" if the foo is neither
 % missing or Top.  Thus, @xref{,,,foo,The Foo Manual} outputs simply
 % "see The Foo Manual", the idea being to refer to the whole manual.
-% 
+%
 % But, this being TeX, we can't easily compare our node name against the
 % string "Top" while ignoring the possible spaces before and after in
 % the input.  By adding the arbitrary 7sp below, we make it much less
 % likely that a real node name would have the same width as "Top" (e.g.,
 % in a monospaced font).  Hopefully it will never happen in practice.
-% 
+%
 % For the same basic reason, we retypeset the "Top" at every
 % reference, since the current font is indeterminate.
-% 
+%
 \def\crossmanualxref#1{%
   \setbox\toprefbox = \hbox{Top\kern7sp}%
   \setbox2 = \hbox{\ignorespaces \printedrefname \unskip \kern7sp}%
@@ -9129,7 +9049,7 @@ end
   \fi\fi\fi
 }
 
-% \refx{NAME}{SUFFIX} - reference a cross-reference string named NAME.  SUFFIX 
+% \refx{NAME}{SUFFIX} - reference a cross-reference string named NAME.  SUFFIX
 % is output afterwards if non-empty.
 \def\refx#1#2{%
   \requireauxfile
@@ -9161,9 +9081,9 @@ end
   #2% Output the suffix in any case.
 }
 
-% This is the macro invoked by entries in the aux file.  Define a control 
-% sequence for a cross-reference target (we prepend XR to the control sequence 
-% name to avoid collisions).  The value is the page number.  If this is a float 
+% This is the macro invoked by entries in the aux file.  Define a control
+% sequence for a cross-reference target (we prepend XR to the control sequence
+% name to avoid collisions).  The value is the page number.  If this is a float
 % type, we have more work to do.
 %
 \def\xrdef#1#2{%
@@ -9179,10 +9099,10 @@ end
   \bgroup
     \expandafter\gdef\csname XR\safexrefname\endcsname{#2}%
   \egroup
-  % We put the \gdef inside a group to avoid the definitions building up on 
-  % TeX's save stack, which can cause it to run out of space for aux files with 
+  % We put the \gdef inside a group to avoid the definitions building up on
+  % TeX's save stack, which can cause it to run out of space for aux files with
   % thousands of lines.  \gdef doesn't use the save stack, but \csname does
-  % when it defines an unknown control sequence as \relax. 
+  % when it defines an unknown control sequence as \relax.
   %
   % Was that xref control sequence that we just defined for a float?
   \expandafter\iffloat\csname XR\safexrefname\endcsname
@@ -9261,19 +9181,6 @@ end
   \catcode`\^^]=\other
   \catcode`\^^^=\other
   \catcode`\^^_=\other
-  % It was suggested to set the catcode of ^ to 7, which would allow ^^e4 etc.
-  % in xref tags, i.e., node names.  But since ^^e4 notation isn't
-  % supported in the main text, it doesn't seem desirable.  Furthermore,
-  % that is not enough: for node names that actually contain a ^
-  % character, we would end up writing a line like this: 'xrdef {'hat
-  % b-title}{'hat b} and \xrdef does a \csname...\endcsname on the first
-  % argument, and \hat is not an expandable control sequence.  It could
-  % all be worked out, but why?  Either we support ^^ or we don't.
-  %
-  % The other change necessary for this was to define \auxhat:
-  % \def\auxhat{\def^{'hat }}% extra space so ok if followed by letter
-  % and then to call \auxhat in \setq.
-  %
   \catcode`\^=\other
   %
   % Special characters.  Should be turned off anyway, but...
@@ -9291,14 +9198,7 @@ end
   \catcode`\%=\other
   \catcode`+=\other % avoid \+ for paranoia even though we've turned it off
   %
-  % This is to support \ in node names and titles, since the \
-  % characters end up in a \csname.  It's easier than
-  % leaving it active and making its active definition an actual \
-  % character.  What I don't understand is why it works in the *value*
-  % of the xrdef.  Seems like it should be a catcode12 \, and that
-  % should not typeset properly.  But it works, so I'm moving on for
-  % now.  --karl, 15jan04.
-  \catcode`\\=\other
+  \catcode`\\=\active
   %
   % @ is our escape character in .aux files, and we need braces.
   \catcode`\{=1
@@ -9561,7 +9461,7 @@ end
   %
   \ifimagevmode
     \medskip  % space after a standalone image
-  \fi  
+  \fi
   \ifx\centersub\centerV \egroup \fi
 \endgroup}
 
@@ -9629,13 +9529,13 @@ end
       \global\advance\floatno by 1
       %
       {%
-        % This magic value for \lastsection is output by \setref as the
+        % This magic value for \currentsection is output by \setref as the
         % XREFLABEL-title value.  \xrefX uses it to distinguish float
         % labels (which have a completely different output format) from
         % node and anchor labels.  And \xrdef uses it to construct the
         % lists of floats.
         %
-        \edef\lastsection{\floatmagic=\safefloattype}%
+        \edef\currentsection{\floatmagic=\safefloattype}%
         \setref{\floatlabel}{Yfloat}%
       }%
     \fi
@@ -9758,7 +9658,7 @@ end
 
 % #1 is the control sequence we are passed; we expand into a conditional
 % which is true if #1 represents a float ref.  That is, the magic
-% \lastsection value which we \setref above.
+% \currentsection value which we \setref above.
 %
 \def\iffloat#1{\expandafter\doiffloat#1==\finish}
 %
@@ -10392,7 +10292,7 @@ directory should work if nowhere else does.}
         \uppercase{.}
       \endgroup
     \else
-      \errhelp = \EMsimple	
+      \errhelp = \EMsimple
       \errmessage{Unicode character U+#1 not supported, sorry}%
     \fi
   \else
@@ -10425,7 +10325,7 @@ directory should work if nowhere else does.}
     \countUTFz = "#1\relax
     \begingroup
       \parseXMLCharref
-    
+
       % Give \u8:... its definition.  The sequence of seven \expandafter's
       % expands after the \gdef three times, e.g.
       %
@@ -10437,7 +10337,7 @@ directory should work if nowhere else does.}
       \expandafter\expandafter
       \expandafter\expandafter
       \expandafter\gdef       \UTFviiiTmp{#2}%
-      % 
+      %
       \expandafter\ifx\csname uni:#1\endcsname \relax \else
        \message{Internal error, already defined: #1}%
       \fi
@@ -10476,7 +10376,7 @@ directory should work if nowhere else does.}
     \divide\countUTFz by 64
     \countUTFy = \countUTFz  % Save to be the future value of \countUTFz.
     \multiply\countUTFz by 64
-    
+
     % \countUTFz is now \countUTFx with the last 5 bits cleared.  Subtract
     % in order to get the last five bits.
     \advance\countUTFx by -\countUTFz
@@ -10511,7 +10411,7 @@ directory should work if nowhere else does.}
 % U+0080..U+00FF = https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)
 % U+0100..U+017F = https://en.wikipedia.org/wiki/Latin_Extended-A
 % U+0180..U+024F = https://en.wikipedia.org/wiki/Latin_Extended-B
-% 
+%
 % Many of our renditions are less than wonderful, and all the missing
 % characters are available somewhere.  Loading the necessary fonts
 % awaits user request.  We can't truly support Unicode without
@@ -11246,21 +11146,14 @@ directory should work if nowhere else does.}
    \relax
 }
 
-% define all Unicode characters we know about, for the sake of @U.
+% Define all Unicode characters we know about.  This makes UTF-8 the default
+% input encoding and allows @U to work.
 \iftxinativeunicodecapable
   \nativeunicodechardefsatu
 \else
   \utfeightchardefs
 \fi
 
-
-% Make non-ASCII characters printable again for compatibility with
-% existing Texinfo documents that may use them, even without declaring a
-% document encoding.
-%
-\setnonasciicharscatcode \other
-
-
 \message{formatting,}
 
 \newdimen\defaultparindent \defaultparindent = 15pt
@@ -11556,9 +11449,9 @@ directory should work if nowhere else does.}
 \def\texinfochars{%
   \let< = \activeless
   \let> = \activegtr
-  \let~ = \activetilde 
+  \let~ = \activetilde
   \let^ = \activehat
-  \markupsetuplqdefault \markupsetuprqdefault 
+  \markupsetuplqdefault \markupsetuprqdefault
   \let\b = \strong
   \let\i = \smartitalic
   % in principle, all other definitions in \tex have to be undone too.
@@ -11576,11 +11469,9 @@ directory should work if nowhere else does.}
 % \backslashcurfont outputs one backslash character in current font,
 % as in \char`\\.
 \global\chardef\backslashcurfont=`\\
-\global\let\rawbackslashxx=\backslashcurfont  % let existing .??s files work
 
-% \realbackslash is an actual character `\' with catcode other, and
-% \doublebackslash is two of them (for the pdf outlines).
-{\catcode`\\=\other @gdef@realbackslash{\} @gdef@doublebackslash{\\}}
+% \realbackslash is an actual character `\' with catcode other.
+{\catcode`\\=\other @gdef@realbackslash{\}}
 
 % In Texinfo, backslash is an active character; it prints the backslash
 % in fixed width font.
@@ -11598,10 +11489,8 @@ directory should work if nowhere else does.}
 @def@ttbackslash{{@tt @ifmmode @mathchar29020 @else @backslashcurfont @fi}}
 @let@backslashchar = @ttbackslash % @backslashchar{} is for user documents.
 
-% \rawbackslash defines an active \ to do \backslashcurfont.
 % \otherbackslash defines an active \ to be a literal `\' character with
-% catcode other.  We switch back and forth between these.
-@gdef@rawbackslash{@let\=@backslashcurfont}
+% catcode other.
 @gdef@otherbackslash{@let\=@realbackslash}
 
 % Same as @turnoffactive except outputs \ as {\tt\char`\\} instead of
@@ -11673,7 +11562,7 @@ directory should work if nowhere else does.}
   @ifx\@eatinput @let\ = @ttbackslash @fi
   @catcode13=5 % regular end of line
   @enableemergencynewline
-  @let@c=@texinfoc
+  @let@c=@comment
   @let@parsearg@originalparsearg
   % Also turn back on active characters that might appear in the input
   % file name, in case not using a pre-dumped format.
diff --git a/build-aux/update-copyright b/build-aux/update-copyright
index f2fc97e..4f79b56 100755
--- a/build-aux/update-copyright
+++ b/build-aux/update-copyright
@@ -1,11 +1,9 @@
-eval '(exit $?0)' && eval 'exec perl -wS -0777 -pi "$0" "$@"'
-  & eval 'exec perl -wS -0777 -pi "$0" $argv:q'
-    if 0;
-# Update an FSF copyright year list to include the current year.
+#!/bin/sh
+#! -*-perl-*-
 
-my $VERSION = '2018-03-07.03:47'; # UTC
+# Update an FSF copyright year list to include the current year.
 
-# Copyright (C) 2009-2018 Free Software Foundation, Inc.
+# Copyright (C) 2009-2020 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -19,9 +17,12 @@ my $VERSION = '2018-03-07.03:47'; # UTC
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
+#
 # Written by Jim Meyering and Joel E. Denny
 
+# This script updates an FSF copyright year list to include the current year.
+# Usage: update-copyright [FILE...]
+#
 # The arguments to this script should be names of files that contain
 # copyright statements to be updated.  The copyright holder's name
 # defaults to "Free Software Foundation, Inc." but may be changed to
@@ -97,7 +98,7 @@ my $VERSION = '2018-03-07.03:47'; # UTC
 #   6. Blank lines, even if preceded by the prefix, do not appear
 #      within the FSF copyright statement.
 #   7. Each copyright year is 2 or 4 digits, and years are separated by
-#      commas or dashes.  Whitespace may appear after commas.
+#      commas, "-", or "--".  Whitespace may appear after commas.
 #
 # Environment variables:
 #
@@ -121,6 +122,27 @@ my $VERSION = '2018-03-07.03:47'; # UTC
 #   5. Set UPDATE_COPYRIGHT_HOLDER if the copyright holder is other
 #      than "Free Software Foundation, Inc.".
 
+# This is a prologue that allows to run a perl script as an executable
+# on systems that are compliant to a POSIX version before POSIX:2017.
+# On such systems, the usual invocation of an executable through execlp()
+# or execvp() fails with ENOEXEC if it is a script that does not start
+# with a #! line.  The script interpreter mentioned in the #! line has
+# to be /bin/sh, because on GuixSD systems that is the only program that
+# has a fixed file name.  The second line is essential for perl and is
+# also useful for editing this file in Emacs.  The next two lines below
+# are valid code in both sh and perl.  When executed by sh, they re-execute
+# the script through the perl program found in $PATH.  The '-x' option
+# is essential as well; without it, perl would re-execute the script
+# through /bin/sh.  When executed by  perl, the next two lines are a no-op.
+eval 'exec perl -wSx -0777 -pi "$0" "$@"'
+     if 0;
+
+my $VERSION = '2018-03-07.03:47'; # UTC
+# The definition above must lie within the first 8 lines in order
+# for the Emacs time-stamp write hook (at end) to update it.
+# If you change this file with Emacs, please let the write hook
+# do its job.  Otherwise, update this string manually.
+
 use strict;
 use warnings;
 
@@ -170,7 +192,7 @@ while (/(^|\n)(.{0,$prefix_max})$copyright_re/g)
     $holder_re =~ s/\s/$ws_re/g;
     my $stmt_remainder_re =
       "(?:$ws_re$circle_c_re)?"
-      . "$ws_re(?:(?:\\d\\d)?\\d\\d(?:,$ws_re?|-))*"
+      . "$ws_re(?:(?:\\d\\d)?\\d\\d(?:,$ws_re?|--?))*"
       . "((?:\\d\\d)?\\d\\d)$ws_re$holder_re";
     if (/\G$stmt_remainder_re/)
       {
@@ -209,26 +231,28 @@ if (defined $stmt_re)
         # Make the use of intervals consistent.
         if (!$ENV{UPDATE_COPYRIGHT_USE_INTERVALS})
           {
-            $stmt =~ s/(\d{4})-(\d{4})/join(', ', $1..$2)/eg;
+            $stmt =~ s/(\d{4})--?(\d{4})/join(', ', $1..$2)/eg;
           }
         else
           {
+            my $ndash = $ARGV =~ /\.tex(i(nfo)?)?$/ ? "--" : "-";
+
             $stmt =~
               s/
                 (\d{4})
                 (?:
-                  (,\ |-)
+                  (,\ |--?)
                   ((??{
-                    if    ($2 eq '-') { '\d{4}'; }
+                    if   ($2 ne ', ') { '\d{4}'; }
                     elsif (!$3)       { $1 + 1;  }
                     else              { $3 + 1;  }
                   }))
                 )+
-              /$1-$3/gx;
+              /$1$ndash$3/gx;
 
             # When it's 2, emit a single range encompassing all year numbers.
             $ENV{UPDATE_COPYRIGHT_USE_INTERVALS} == 2
-              and $stmt =~ s/\b(\d{4})\b.*\b(\d{4})\b/$1-$2/;
+              and $stmt =~ s/\b(\d{4})\b.*\b(\d{4})\b/$1$ndash$2/;
           }
 
         # Format within margin.
@@ -270,6 +294,7 @@ else
 # mode: perl
 # indent-tabs-mode: nil
 # eval: (add-hook 'before-save-hook 'time-stamp)
+# time-stamp-line-limit: 200
 # time-stamp-start: "my $VERSION = '"
 # time-stamp-format: "%:y-%02m-%02d.%02H:%02M"
 # time-stamp-time-zone: "UTC0"
diff --git a/build-aux/useless-if-before-free b/build-aux/useless-if-before-free
index 2d4d13f..fa9a368 100755
--- a/build-aux/useless-if-before-free
+++ b/build-aux/useless-if-before-free
@@ -1,32 +1,47 @@
-eval '(exit $?0)' && eval 'exec perl -wST "$0" "$@"'
-  & eval 'exec perl -wST "$0" $argv:q'
-    if 0;
+#!/bin/sh
+#! -*-perl-*-
+
 # Detect instances of "if (p) free (p);".
 # Likewise "if (p != 0)", "if (0 != p)", or with NULL; and with braces.
 
-my $VERSION = '2018-03-07 03:47'; # UTC
-# The definition above must lie within the first 8 lines in order
-# for the Emacs time-stamp write hook (at end) to update it.
-# If you change this file with Emacs, please let the write hook
-# do its job.  Otherwise, update this string manually.
-
-# Copyright (C) 2008-2018 Free Software Foundation, Inc.
-
+# Copyright (C) 2008-2020 Free Software Foundation, Inc.
+#
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
-
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
-
+#
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
+#
 # Written by Jim Meyering
 
+# This is a prologue that allows to run a perl script as an executable
+# on systems that are compliant to a POSIX version before POSIX:2017.
+# On such systems, the usual invocation of an executable through execlp()
+# or execvp() fails with ENOEXEC if it is a script that does not start
+# with a #! line.  The script interpreter mentioned in the #! line has
+# to be /bin/sh, because on GuixSD systems that is the only program that
+# has a fixed file name.  The second line is essential for perl and is
+# also useful for editing this file in Emacs.  The next two lines below
+# are valid code in both sh and perl.  When executed by sh, they re-execute
+# the script through the perl program found in $PATH.  The '-x' option
+# is essential as well; without it, perl would re-execute the script
+# through /bin/sh.  When executed by  perl, the next two lines are a no-op.
+eval 'exec perl -wSx "$0" "$@"'
+     if 0;
+
+my $VERSION = '2018-03-07 03:47'; # UTC
+# The definition above must lie within the first 8 lines in order
+# for the Emacs time-stamp write hook (at end) to update it.
+# If you change this file with Emacs, please let the write hook
+# do its job.  Otherwise, update this string manually.
+
 use strict;
 use warnings;
 use Getopt::Long;
@@ -203,6 +218,7 @@ EOF
 ## mode: perl
 ## indent-tabs-mode: nil
 ## eval: (add-hook 'before-save-hook 'time-stamp)
+## time-stamp-line-limit: 50
 ## time-stamp-start: "my $VERSION = '"
 ## time-stamp-format: "%:y-%02m-%02d %02H:%02M"
 ## time-stamp-time-zone: "UTC0"
diff --git a/build-aux/vc-list-files b/build-aux/vc-list-files
index 12f191b..a8b8d9a 100755
--- a/build-aux/vc-list-files
+++ b/build-aux/vc-list-files
@@ -4,7 +4,7 @@
 # Print a version string.
 scriptversion=2018-03-07.03; # UTC
 
-# Copyright (C) 2006-2018 Free Software Foundation, Inc.
+# Copyright (C) 2006-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -25,7 +25,7 @@ scriptversion=2018-03-07.03; # UTC
 # list the version-controlled files in that directory.
 
 # If there's an argument, it must be a single, "."-relative directory name.
-# cvsu is part of the cvsutils package: http://www.red-bean.com/cvsutils/
+# cvsu is part of the cvsutils package: https://www.red-bean.com/cvsutils/
 
 postprocess=
 case $1 in