--- /dev/null
+# ===========================================================================
+# http://www.gnu.org/software/autoconf-archive/ax_c___attribute__.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+# AX_C___ATTRIBUTE__
+#
+# DESCRIPTION
+#
+# Provides a test for the compiler support of __attribute__ extensions.
+# Defines HAVE___ATTRIBUTE__ if it is found.
+#
+# LICENSE
+#
+# Copyright (c) 2008 Stepan Kasal <skasal@redhat.com>
+# Copyright (c) 2008 Christian Haggstrom
+# Copyright (c) 2008 Ryan McCabe <ryan@numb.org>
+#
+# 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 2 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 <http://www.gnu.org/licenses/>.
+#
+# As a special exception, the respective Autoconf Macro's copyright owner
+# gives unlimited permission to copy, distribute and modify the configure
+# scripts that are the output of Autoconf when processing the Macro. You
+# need not follow the terms of the GNU General Public License when using
+# or distributing such scripts, even though portions of the text of the
+# Macro appear in them. The GNU General Public License (GPL) does govern
+# all other use of the material that constitutes the Autoconf Macro.
+#
+# This special exception to the GPL applies to versions of the Autoconf
+# Macro released by the Autoconf Archive. When you make and distribute a
+# modified version of the Autoconf Macro, you may extend this special
+# exception to the GPL to apply to your modified version as well.
+
+#serial 8
+
+AC_DEFUN([AX_C___ATTRIBUTE__], [
+ AC_CACHE_CHECK([for __attribute__], [ax_cv___attribute__],
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <stdlib.h>
+ static void foo(void) __attribute__ ((unused));
+ static void
+ foo(void) {
+ exit(1);
+ }
+ ]], [])],
+ [ax_cv___attribute__=yes],
+ [ax_cv___attribute__=no]
+ )
+ ])
+ if test "$ax_cv___attribute__" = "yes"; then
+ AC_DEFINE([HAVE___ATTRIBUTE__], 1, [define if your compiler has __attribute__])
+ fi
+])