[Emacs-diffs] master 9d56a21: Merge from gnulib

[Paul Eggert]

branch: master
commit 9d56a21e6a696ad19ac65c4b405aeca44785884a
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>

    Merge from gnulib
    
    * lib/stddef.in.h: Update from gnulib, incorporating:
    2015-04-02 stddef: port to pre-C11 GCC on x86
---
 ChangeLog       |    6 ++++++
 lib/stddef.in.h |   19 +++++++++++++++----
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 70ab50c..6e2b4fc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2015-04-07  Paul Eggert  <address@hidden>
+
+       Merge from gnulib
+       * lib/stddef.in.h: Update from gnulib, incorporating:
+       2015-04-02 stddef: port to pre-C11 GCC on x86
+
 2015-04-03  Paul Eggert  <address@hidden>
 
        Port 'configure' to clang 3.5
diff --git a/lib/stddef.in.h b/lib/stddef.in.h
index 44db241..698307b 100644
--- a/lib/stddef.in.h
+++ b/lib/stddef.in.h
@@ -83,12 +83,23 @@
 
 /* Some platforms lack max_align_t.  */
 #if address@hidden@
+/* 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