expedite/m4/ac_attribute.m4

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dnl Copyright (C) 2004-2008 Kim Woelders
dnl Copyright (C) 2008 Vincent Torri <vtorri at univ-evry dot fr>
dnl That code is public domain and can be freely used or copied.
dnl Originally snatched from somewhere...
dnl Macro for checking if the compiler supports __attribute__
dnl Usage: AC_C___ATTRIBUTE__
dnl call AC_DEFINE for HAVE___ATTRIBUTE__ and __UNUSED__
dnl if the compiler supports __attribute__, HAVE___ATTRIBUTE__ is
dnl defined to 1 and __UNUSED__ is defined to __attribute__((unused))
dnl otherwise, HAVE___ATTRIBUTE__ is not defined and __UNUSED__ is
dnl defined to nothing.
AC_DEFUN([AC_C___ATTRIBUTE__],
[
AC_MSG_CHECKING([for __attribute__])
AC_CACHE_VAL([ac_cv___attribute__],
[AC_TRY_COMPILE(
[
#include <stdlib.h>
int func(int x);
int foo(int x __attribute__ ((unused)))
{
exit(1);
}
],
[],
[ac_cv___attribute__="yes"],
[ac_cv___attribute__="no"]
)])
AC_MSG_RESULT($ac_cv___attribute__)
if test "x${ac_cv___attribute__}" = "xyes" ; then
AC_DEFINE([HAVE___ATTRIBUTE__], [1], [Define to 1 if your compiler has __attribute__])
AC_DEFINE([__UNUSED__], [__attribute__((unused))], [Macro declaring a function argument to be unused])
else
AC_DEFINE([__UNUSED__], [], [Macro declaring a function argument to be unused])
fi
])
dnl End of ac_attribute.m4