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+dnl Macros to check the presence of generic (non-typed) symbols.
+dnl Copyright (c) 2006-2008 Diego Pettenò <flameeyes@gmail.com>
+dnl Copyright (c) 2006-2008 xine project
+dnl Copyright (c) 2012 Lucas De Marchi <lucas.de.marchi@gmail.com>
+dnl
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 2, or (at your option)
+dnl any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+dnl GNU General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program; if not, write to the Free Software
+dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+dnl 02110-1301, USA.
+dnl
+dnl As a special exception, the copyright owners of the
+dnl macro gives unlimited permission to copy, distribute and modify the
+dnl configure scripts that are the output of Autoconf when processing the
+dnl Macro. You need not follow the terms of the GNU General Public
+dnl License when using or distributing such scripts, even though portions
+dnl of the text of the Macro appear in them. The GNU General Public
+dnl License (GPL) does govern all other use of the material that
+dnl constitutes the Autoconf Macro.
+dnl
+dnl This special exception to the GPL applies to versions of the
+dnl Autoconf Macro released by this project. When you make and
+dnl distribute a modified version of the Autoconf Macro, you may extend
+dnl this special exception to the GPL to apply to your modified version as
+dnl well.
+
+dnl Check if FLAG in ENV-VAR is supported by compiler and append it
+dnl to WHERE-TO-APPEND variable
+dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG])
+
+AC_DEFUN([CC_CHECK_FLAG_APPEND], [
+ AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2],
+ AS_TR_SH([cc_cv_$2_$3]),
+ [eval "AS_TR_SH([cc_save_$2])='${$2}'"
+ eval "AS_TR_SH([$2])='$3'"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([int a = 0; int main(void) { return a; } ])],
+ [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
+ [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
+ eval "AS_TR_SH([$2])='$cc_save_$2'"])
+
+ AS_IF([eval test x$]AS_TR_SH([cc_cv_$2_$3])[ = xyes],
+ [eval "$1='${$1} $3'"])
+])
+
+dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2])
+AC_DEFUN([CC_CHECK_FLAGS_APPEND], [
+ for flag in $3; do
+ CC_CHECK_FLAG_APPEND($1, $2, $flag)
+ done
+])
+
+dnl Check if the flag is supported by linker (cacheable)
+dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
+
+AC_DEFUN([CC_CHECK_LDFLAGS], [
+ AC_CACHE_CHECK([if $CC supports $1 flag],
+ AS_TR_SH([cc_cv_ldflags_$1]),
+ [ac_save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$LDFLAGS $1"
+ AC_LINK_IFELSE([int main() { return 1; }],
+ [eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"],
+ [eval "AS_TR_SH([cc_cv_ldflags_$1])="])
+ LDFLAGS="$ac_save_LDFLAGS"
+ ])
+
+ AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
+ [$2], [$3])
+])
+
+dnl define the LDFLAGS_NOUNDEFINED variable with the correct value for
+dnl the current linker to avoid undefined references in a shared object.
+AC_DEFUN([CC_NOUNDEFINED], [
+ dnl We check $host for which systems to enable this for.
+ AC_REQUIRE([AC_CANONICAL_HOST])
+
+ case $host in
+ dnl FreeBSD (et al.) does not complete linking for shared objects when pthreads
+ dnl are requested, as different implementations are present; to avoid problems
+ dnl use -Wl,-z,defs only for those platform not behaving this way.
+ *-freebsd* | *-openbsd*) ;;
+ *)
+ dnl First of all check for the --no-undefined variant of GNU ld. This allows
+ dnl for a much more readable commandline, so that people can understand what
+ dnl it does without going to look for what the heck -z defs does.
+ for possible_flags in "-Wl,--no-undefined" "-Wl,-z,defs"; do
+ CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"])
+ break
+ done
+ ;;
+ esac
+
+ AC_SUBST([LDFLAGS_NOUNDEFINED])
+])
+
+dnl Check for a -Werror flag or equivalent. -Werror is the GCC
+dnl and ICC flag that tells the compiler to treat all the warnings
+dnl as fatal. We usually need this option to make sure that some
+dnl constructs (like attributes) are not simply ignored.
+dnl
+dnl Other compilers don't support -Werror per se, but they support
+dnl an equivalent flag:
+dnl - Sun Studio compiler supports -errwarn=%all
+AC_DEFUN([CC_CHECK_WERROR], [
+ AC_CACHE_CHECK(
+ [for $CC way to treat warnings as errors],
+ [cc_cv_werror],
+ [CC_CHECK_CFLAGS_SILENT([-Werror], [cc_cv_werror=-Werror],
+ [CC_CHECK_CFLAGS_SILENT([-errwarn=%all], [cc_cv_werror=-errwarn=%all])])
+ ])
+])
+
+AC_DEFUN([CC_CHECK_ATTRIBUTE], [
+ AC_REQUIRE([CC_CHECK_WERROR])
+ AC_CACHE_CHECK([if $CC supports __attribute__(( ifelse([$2], , [$1], [$2]) ))],
+ AS_TR_SH([cc_cv_attribute_$1]),
+ [ac_save_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS $cc_cv_werror"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([$3])],
+ [eval "AS_TR_SH([cc_cv_attribute_$1])='yes'"],
+ [eval "AS_TR_SH([cc_cv_attribute_$1])='no'"])
+ CFLAGS="$ac_save_CFLAGS"
+ ])
+
+ AS_IF([eval test x$]AS_TR_SH([cc_cv_attribute_$1])[ = xyes],
+ [AC_DEFINE(
+ AS_TR_CPP([SUPPORT_ATTRIBUTE_$1]), 1,
+ [Define this if the compiler supports __attribute__(( ifelse([$2], , [$1], [$2]) ))]
+ )
+ $4],
+ [$5])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
+ CC_CHECK_ATTRIBUTE(
+ [constructor],,
+ [void __attribute__((constructor)) ctor() { int a; }],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
+ CC_CHECK_ATTRIBUTE(
+ [format], [format(printf, n, n)],
+ [void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { fmt = (void *)0; }],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
+ CC_CHECK_ATTRIBUTE(
+ [format_arg], [format_arg(printf)],
+ [char *__attribute__((format_arg(1))) gettextlike(const char *fmt) { fmt = (void *)0; }],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
+ CC_CHECK_ATTRIBUTE(
+ [visibility_$1], [visibility("$1")],
+ [void __attribute__((visibility("$1"))) $1_function() { }],
+ [$2], [$3])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
+ CC_CHECK_ATTRIBUTE(
+ [nonnull], [nonnull()],
+ [void __attribute__((nonnull())) some_function(void *foo, void *bar) { foo = (void*)0; bar = (void*)0; }],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
+ CC_CHECK_ATTRIBUTE(
+ [unused], ,
+ [void some_function(void *foo, __attribute__((unused)) void *bar);],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
+ CC_CHECK_ATTRIBUTE(
+ [sentinel], ,
+ [void some_function(void *foo, ...) __attribute__((sentinel));],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [
+ CC_CHECK_ATTRIBUTE(
+ [deprecated], ,
+ [void some_function(void *foo, ...) __attribute__((deprecated));],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_ALIAS], [
+ CC_CHECK_ATTRIBUTE(
+ [alias], [weak, alias],
+ [void other_function(void *foo) { }
+ void some_function(void *foo) __attribute__((weak, alias("other_function")));],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_MALLOC], [
+ CC_CHECK_ATTRIBUTE(
+ [malloc], ,
+ [void * __attribute__((malloc)) my_alloc(int n);],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_PACKED], [
+ CC_CHECK_ATTRIBUTE(
+ [packed], ,
+ [struct astructure { char a; int b; long c; void *d; } __attribute__((packed));],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_CONST], [
+ CC_CHECK_ATTRIBUTE(
+ [const], ,
+ [int __attribute__((const)) twopow(int n) { return 1 << n; } ],
+ [$1], [$2])
+])
+
+AC_DEFUN([CC_FLAG_VISIBILITY], [
+ AC_REQUIRE([CC_CHECK_WERROR])
+ AC_CACHE_CHECK([if $CC supports -fvisibility=hidden],
+ [cc_cv_flag_visibility],
+ [cc_flag_visibility_save_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS $cc_cv_werror"
+ CC_CHECK_CFLAGS_SILENT([-fvisibility=hidden],
+ cc_cv_flag_visibility='yes',
+ cc_cv_flag_visibility='no')
+ CFLAGS="$cc_flag_visibility_save_CFLAGS"])
+
+ AS_IF([test "x$cc_cv_flag_visibility" = "xyes"],
+ [AC_DEFINE([SUPPORT_FLAG_VISIBILITY], 1,
+ [Define this if the compiler supports the -fvisibility flag])
+ $1],
+ [$2])
+])
+
+AC_DEFUN([CC_FUNC_EXPECT], [
+ AC_REQUIRE([CC_CHECK_WERROR])
+ AC_CACHE_CHECK([if compiler has __builtin_expect function],
+ [cc_cv_func_expect],
+ [ac_save_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS $cc_cv_werror"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE(
+ [int some_function() {
+ int a = 3;
+ return (int)__builtin_expect(a, 3);
+ }])],
+ [cc_cv_func_expect=yes],
+ [cc_cv_func_expect=no])
+ CFLAGS="$ac_save_CFLAGS"
+ ])
+
+ AS_IF([test "x$cc_cv_func_expect" = "xyes"],
+ [AC_DEFINE([SUPPORT__BUILTIN_EXPECT], 1,
+ [Define this if the compiler supports __builtin_expect() function])
+ $1],
+ [$2])
+])
+
+AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [
+ AC_REQUIRE([CC_CHECK_WERROR])
+ AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported],
+ [cc_cv_attribute_aligned],
+ [ac_save_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS $cc_cv_werror"
+ for cc_attribute_align_try in 64 32 16 8 4 2; do
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+ int main() {
+ static char c __attribute__ ((aligned($cc_attribute_align_try))) = 0;
+ return c;
+ }])], [cc_cv_attribute_aligned=$cc_attribute_align_try; break])
+ done
+ CFLAGS="$ac_save_CFLAGS"
+ ])
+
+ if test "x$cc_cv_attribute_aligned" != "x"; then
+ AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX], [$cc_cv_attribute_aligned],
+ [Define the highest alignment supported])
+ fi
+])
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