diff options
Diffstat (limited to 'm4/stdalign.m4')
| -rw-r--r-- | m4/stdalign.m4 | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/m4/stdalign.m4 b/m4/stdalign.m4 index 2683fae7daf..e3c1e609236 100644 --- a/m4/stdalign.m4 +++ b/m4/stdalign.m4 @@ -13,10 +13,10 @@ AC_DEFUN([gl_ALIGNASOF], [ AC_CACHE_CHECK([for alignas and alignof], [gl_cv_header_working_stdalign_h], - [gl_save_CFLAGS=$CFLAGS + [gl_saved_CFLAGS=$CFLAGS for gl_working in "yes, keywords" "yes, <stdalign.h> macros"; do AS_CASE([$gl_working], - [*stdalign.h*], [CFLAGS="$gl_save_CFLAGS -DINCLUDE_STDALIGN_H"]) + [*stdalign.h*], [CFLAGS="$gl_saved_CFLAGS -DINCLUDE_STDALIGN_H"]) AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( [[#include <stdint.h> @@ -56,7 +56,7 @@ AC_DEFUN([gl_ALIGNASOF], [gl_cv_header_working_stdalign_h=$gl_working], [gl_cv_header_working_stdalign_h=no]) - CFLAGS=$gl_save_CFLAGS + CFLAGS=$gl_saved_CFLAGS test "$gl_cv_header_working_stdalign_h" != no && break done]) @@ -112,7 +112,11 @@ AC_DEFUN([gl_ALIGNASOF], # define _Alignof(type) alignof (type) # else template <class __t> struct __alignof_helper { char __a; __t __b; }; -# define _Alignof(type) offsetof (__alignof_helper<type>, __b) +# if (defined __GNUC__ && 4 <= __GNUC__) || defined __clang__ +# define _Alignof(type) __builtin_offsetof (__alignof_helper<type>, __b) +# else +# define _Alignof(type) offsetof (__alignof_helper<type>, __b) +# endif # define _GL_STDALIGN_NEEDS_STDDEF 1 # endif # else |