* test/lisp/help-fns-tests.el: Add several tests for 'describe-function'.

[gnu-emacs] / lib / stddef.in.h

diff --git a/lib/stddef.in.h b/lib/stddef.in.h
index 9924a327fca06c171c1f06ad3ef35cb1a2ce2a1a..f4c4a1070d5ba801090fe1add31c82d050d49156 100644 (file)
--- a/lib/stddef.in.h
+++ b/lib/stddef.in.h
@@ -1,6 +1,6 @@
 /* A substitute for POSIX 2008 <stddef.h>, for platforms that have issues.
 
-   Copyright (C) 2009-2014 Free Software Foundation, Inc.
+   Copyright (C) 2009-2016 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -81,14 +81,27 @@
 # define wchar_t int
 #endif
 
-/* Some platforms lack max_align_t.  */
-#if !@HAVE_MAX_ALIGN_T@
+/* Some platforms lack max_align_t.  The check for _GCC_MAX_ALIGN_T is
+   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)
+/* 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
 typedef union
 {
-  char *__p;
-  double __d;
-  long double __ld;
-  long int __i;
+  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;
 #endif