dnl @synopsis XIPH_GCC_REALLY_IS_GCC

dnl

dnl Find out if a compiler claiming to be gcc really is gcc (clang lies).

dnl @version 1.0 Oct 31 2013

dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>

dnl

dnl Permission to use, copy, modify, distribute, and sell this file for any

dnl purpose is hereby granted without fee, provided that the above copyright

dnl and this permission notice appear in all copies. No representations are

dnl made about the suitability of this software for any purpose. It is

dnl provided "as is" without express or implied warranty.

dnl

# If the configure script has already detected GNU GCC, then make sure it

# isn't CLANG masquerading as GCC.

AC_DEFUN([XIPH_GCC_REALLY_IS_GCC],

[ AC_LANG_ASSERT(C)

if test "x$ac_cv_c_compiler_gnu" = "xyes" ; then

AC_TRY_LINK([

#include <stdio.h>

],

[

#ifdef __clang__

This is clang!

#endif

],

ac_cv_c_compiler_gnu=yes,

ac_cv_c_compiler_gnu=no

)

fi

])