Try to fix FreeBSD 9.1 porting problem.

This incorporates the following merge from gnulib:
2013-07-07 stdalign, verify: port to FreeBSD 9.1, to C11, and to C++11

Fixes: debbugs:14812

1 files changed, 29 insertions, 10 deletions

diff --git a/lib/stdalign.in.h b/lib/stdalign.in.h
index c3a67321b0e..7254a3dec17 100644
--- a/lib/stdalign.in.h
+++ b/lib/stdalign.in.h
@@ -41,13 +41,28 @@
    are 4 unless the option '-malign-double' is used.
 
    The result cannot be used as a value for an 'enum' constant, if you
-   want to be portable to HP-UX 10.20 cc and AIX 3.2.5 xlc.  */
+   want to be portable to HP-UX 10.20 cc and AIX 3.2.5 xlc.
+
+   Include <stddef.h> for offsetof.  */
 #include <stddef.h>
-#if defined __cplusplus
+
+/* FreeBSD 9.1 <sys/cdefs.h>, included by <stddef.h> and lots of other
+   standard headers, defines conflicting implementations of _Alignas
+   and _Alignof that are no better than ours; override them.  */
+#undef _Alignas
+#undef _Alignof
+
+#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
+# ifdef __cplusplus
+#  if 201103 <= __cplusplus
+#   define _Alignof(type) alignof (type)
+#  else
    template <class __t> struct __alignof_helper { char __a; __t __b; };
-# define _Alignof(type) offsetof (__alignof_helper<type>, __b)
-#else
-# define _Alignof(type) offsetof (struct { char __a; type __b; }, __b)
+#   define _Alignof(type) offsetof (__alignof_helper<type>, __b)
+#  endif
+# else
+#  define _Alignof(type) offsetof (struct { char __a; type __b; }, __b)
+# endif
 #endif
 #define alignof _Alignof
 #define __alignof_is_defined 1
@@ -77,12 +92,16 @@
 
    */
 
-#if __GNUC__ || __IBMC__ || __IBMCPP__ || 0x5110 <= __SUNPRO_C
-# define _Alignas(a) __attribute__ ((__aligned__ (a)))
-#elif 1300 <= _MSC_VER
-# define _Alignas(a) __declspec (align (a))
+#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
+# if defined __cplusplus && 201103 <= __cplusplus
+#  define _Alignas(a) alignas (a)
+# elif __GNUC__ || __IBMC__ || __IBMCPP__ || __ICC || 0x5110 <= __SUNPRO_C
+#  define _Alignas(a) __attribute__ ((__aligned__ (a)))
+# elif 1300 <= _MSC_VER
+#  define _Alignas(a) __declspec (align (a))
+# endif
 #endif
-#ifdef _Alignas
+#if defined _Alignas || (defined __STDC_VERSION && 201112 <= __STDC_VERSION__)
 # define alignas _Alignas
 # define __alignas_is_defined 1
 #endif