1dnl @synopsis XIPH_GCC_REALLY_IS_GCC 2dnl 3dnl Find out if a compiler claiming to be gcc really is gcc (clang lies). 4dnl @version 1.0 Oct 31 2013 5dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com> 6dnl 7dnl Permission to use, copy, modify, distribute, and sell this file for any 8dnl purpose is hereby granted without fee, provided that the above copyright 9dnl and this permission notice appear in all copies. No representations are 10dnl made about the suitability of this software for any purpose. It is 11dnl provided "as is" without express or implied warranty. 12dnl 13 14# If the configure script has already detected GNU GCC, then make sure it 15# isn't CLANG masquerading as GCC. 16 17AC_DEFUN([XIPH_GCC_REALLY_IS_GCC], 18[ AC_LANG_ASSERT(C) 19 if test "x$ac_cv_c_compiler_gnu" = "xyes" ; then 20 AC_TRY_LINK([ 21 #include <stdio.h> 22 ], 23 [ 24 #ifdef __clang__ 25 This is clang! 26 #endif 27 ], 28 ac_cv_c_compiler_gnu=yes, 29 ac_cv_c_compiler_gnu=no 30 ) 31 fi 32]) 33