Add 3type to default section list

This is used by the Linux man-pages package, and should be lower
priority than section 2.  Suggested by Alejandro Colomar.

Fixes https://gitlab.com/cjwatson/man-db/-/issues/5.

* include/manconfig.h (STD_SECTIONS): Add `3type` between sections `2`
and `5`.
* m4/man-arg-sections.m4 (MAN_ARG_SECTIONS): Likewise.
* man/man5/manpath.man5 (FORMAT): Update documentation of SECTION.
* src/tests/man-exact-section-matches: Update default section order.
* src/man_db.conf.in (SECTION): Update documentation.
* NEWS.md: Document this.

6 files changed, 13 insertions, 7 deletions

diff --git a/NEWS.md b/NEWS.md
index fc1a3c80..bbf1b050 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -6,6 +6,11 @@ Fixes:
  * SECURITY: Escape `$` characters in page names when constructing `less`
    prompts.  Note that this requires `less` >= 457 (released in 2012).
 
+Improvements:
+
+ * Add section `3type` to the default section list just after `2`.  This is
+   used by the Linux man-pages package.
+
 man-db 2.11.0 (15 October 2022)
 ===============================
 
diff --git a/include/manconfig.h b/include/manconfig.h
index 4f2caea5..8de135f9 100644
--- a/include/manconfig.h
+++ b/include/manconfig.h
@@ -32,7 +32,8 @@
    avoided. */
 
 #define STD_SECTIONS { \
-	"1", "n", "l", "8", "3", "0", "2", "5", "4", "9", "6", "7", NULL \
+	"1", "n", "l", "8", "3", "0", "2", "3type", "5", "4", "9", "6", "7", \
+	NULL \
 }
 
 /* Some system's man pages require default pre-processing with perhaps tbl
diff --git a/m4/man-arg-sections.m4 b/m4/man-arg-sections.m4
index 6d97e6e9..20441b39 100644
--- a/m4/man-arg-sections.m4
+++ b/m4/man-arg-sections.m4
@@ -1,17 +1,17 @@
-# man-arg-sections.m4 serial 2
+# man-arg-sections.m4 serial 3
 dnl MAN_ARG_SECTIONS
 dnl Add a --with-sections option.
 
 AC_DEFUN([MAN_ARG_SECTIONS],
 [
 AC_ARG_WITH([sections],
-[AS_HELP_STRING([--with-sections=SECTIONS], [use manual page sections SECTIONS @<:@1 n l 8 3 0 2 5 4 9 6 7@:>@])],
+[AS_HELP_STRING([--with-sections=SECTIONS], [use manual page sections SECTIONS @<:@1 n l 8 3 0 2 3type 5 4 9 6 7@:>@])],
 	[if test "$withval" = "yes" || test "$withval" = "no"
 	 then
 		AC_MSG_ERROR([--with-sections requires an argument])
 	 else
 		sections="$withval"
 	 fi],
-	[: ${sections=1 n l 8 3 0 2 5 4 9 6 7}])
+	[: ${sections=1 n l 8 3 0 2 3type 5 4 9 6 7}])
 AC_SUBST([sections])dnl
 ])
diff --git a/man/man5/manpath.man5 b/man/man5/manpath.man5
index 0ea293f9..151ebb74 100644
--- a/man/man5/manpath.man5
+++ b/man/man5/manpath.man5
@@ -192,7 +192,7 @@ directives in the configuration file, the default is:
 .PP
 .RS
 .nf
-.if !'po4a'hide' SECTION 1 n l 8 3 0 2 5 4 9 6 7
+.if !'po4a'hide' SECTION 1 n l 8 3 0 2 3type 5 4 9 6 7
 .fi
 .RE
 .PP
diff --git a/src/man_db.conf.in b/src/man_db.conf.in
index 042fc599..3bb8ebd2 100644
--- a/src/man_db.conf.in
+++ b/src/man_db.conf.in
@@ -100,7 +100,7 @@ MANDB_MAP	@snapdir@/man		/var/cache/man/snap
 #DEFINE		apropos_regex_grep_flags	-iE
 #---------------------------------------------------------
 # Section names. Manual sections will be searched in the order listed here;
-# the default is 1, n, l, 8, 3, 0, 2, 5, 4, 9, 6, 7. Multiple SECTION
+# the default is 1, n, l, 8, 3, 0, 2, 3type, 5, 4, 9, 6, 7. Multiple SECTION
 # directives may be given for clarity, and will be concatenated together in
 # the expected way.
 # If a particular extension is not in this list (say, 1mh), it will be
diff --git a/src/tests/man-exact-section-matches b/src/tests/man-exact-section-matches
index 3f74febf..783796e3 100755
--- a/src/tests/man-exact-section-matches
+++ b/src/tests/man-exact-section-matches
@@ -24,7 +24,7 @@ export MANPATH
 
 # Force default section order.
 cat >>"$tmpdir/manpath.config" <<EOF
-SECTION 1 n l 8 3 0 2 5 4 9 6 7
+SECTION 1 n l 8 3 0 2 3type 5 4 9 6 7
 EOF
 
 write_page md5sum 3pm "$tmpdir/usr/share/man/man3/open.3pm.gz" \