+2017-09-08 Bruno Haible <bruno@clisp.org>
+
+ stddef: Avoid conflict with system-defined max_align_t.
+ The configure-determined HAVE_MAX_ALIGN_T may not always be accurate.
+ Reported by Werner Lemberg <wl@gnu.org> in
+ <https://lists.gnu.org/archive/html/bug-gnulib/2017-08/msg00185.html>.
+ * lib/stddef.in.h (rpl_max_align_t): Renamed from max_align_t.
+ (max_align_t): Define as a macro.
+ (GNULIB_defined_max_align_t): New macro. Guards against multiple
+ definitions of rpl_max_align_t in different copies of gnulib-generated
+ <stddef.h>.
+
2017-09-05 Paul Eggert <eggert@cs.ucla.edu>
libc-config: port to MSVC
a hack in case the configure-time test was done with g++ even though
we are currently compiling with gcc. */
#if ! (@HAVE_MAX_ALIGN_T@ || defined _GCC_MAX_ALIGN_T)
+# if !GNULIB_defined_max_align_t
/* On the x86, the maximum storage alignment of double, long, etc. is 4,
but GCC's C11 ABI for x86 says that max_align_t has an alignment of 8,
and the C11 standard allows this. Work around this problem by
using __alignof__ (which returns 8 for double) rather than _Alignof
(which returns 4), and align each union member accordingly. */
-# ifdef __GNUC__
-# define _GL_STDDEF_ALIGNAS(type) \
- __attribute__ ((__aligned__ (__alignof__ (type))))
-# else
-# define _GL_STDDEF_ALIGNAS(type) /* */
-# endif
+# ifdef __GNUC__
+# define _GL_STDDEF_ALIGNAS(type) \
+ __attribute__ ((__aligned__ (__alignof__ (type))))
+# else
+# define _GL_STDDEF_ALIGNAS(type) /* */
+# endif
typedef union
{
char *__p _GL_STDDEF_ALIGNAS (char *);
double __d _GL_STDDEF_ALIGNAS (double);
long double __ld _GL_STDDEF_ALIGNAS (long double);
long int __i _GL_STDDEF_ALIGNAS (long int);
-} max_align_t;
+} rpl_max_align_t;
+# define max_align_t rpl_max_align_t
+# define GNULIB_defined_max_align_t 1
+# endif
#endif
# endif /* _@GUARD_PREFIX@_STDDEF_H */