Use C99-style flexible array members if available.

[bpt/emacs.git] / src / conf_post.h

diff --git a/src/conf_post.h b/src/conf_post.h
index b1997e7..32c4341 100644 (file)
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -1,7 +1,7 @@
 /* conf_post.h --- configure.ac includes this via AH_BOTTOM
 
-Copyright (C) 1988, 1993-1994, 1999-2002, 2004-2012
-  Free Software Foundation, Inc.
+Copyright (C) 1988, 1993-1994, 1999-2002, 2004-2013 Free Software
+Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -40,17 +40,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #endif
 #endif
 
-/* This silences a few compilation warnings on FreeBSD.  */
-#ifdef BSD_SYSTEM_AHB
-#undef BSD_SYSTEM_AHB
-#undef BSD_SYSTEM
-#if __FreeBSD__ == 1
-#define BSD_SYSTEM 199103
-#elif __FreeBSD__ == 2
-#define BSD_SYSTEM 199306
-#elif __FreeBSD__ >= 3
-#define BSD_SYSTEM 199506
-#endif
+#ifndef __has_attribute
+# define __has_attribute(a) 0 /* non-clang */
 #endif
 
 #ifdef DARWIN_OS
@@ -178,10 +169,6 @@ extern void _DebPrint (const char *fmt, ...);
 #endif
 #endif
 
-/* Tell gnulib to omit support for openat-related functions having a
-   first argument other than AT_FDCWD.  */
-#define GNULIB_SUPPORT_ONLY_AT_FDCWD
-
 #include <string.h>
 #include <stdlib.h>
 
@@ -191,7 +178,9 @@ extern void _DebPrint (const char *fmt, ...);
 #define NO_INLINE
 #endif
 
-#if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
+#if (__clang__                                                         \
+     ? __has_attribute (externally_visible)                            \
+     : (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)))
 #define EXTERNALLY_VISIBLE __attribute__((externally_visible))
 #else
 #define EXTERNALLY_VISIBLE
@@ -218,11 +207,53 @@ extern void _DebPrint (const char *fmt, ...);
 #undef noinline
 #endif
 
+/* Use Gnulib's extern-inline module for extern inline functions.
+   An include file foo.h should prepend FOO_INLINE to function
+   definitions, with the following overall pattern:
+
+      [#include any other .h files first.]
+      ...
+      INLINE_HEADER_BEGIN
+      #ifndef FOO_INLINE
+      # define FOO_INLINE INLINE
+      #endif
+      ...
+      FOO_INLINE int
+      incr (int i)
+      {
+        return i + 1;
+      }
+      ...
+      INLINE_HEADER_END
+
+   The corresponding foo.c file should do this:
+
+      #define FOO_INLINE EXTERN_INLINE
+
+   before including any .h file other than config.h.
+   Other .c files should not define FOO_INILNE.
+
+   C99 compilers compile functions like 'incr' as C99-style extern
+   inline functions.  Pre-C99 GCCs do something similar with
+   GNU-specific keywords.  Pre-C99 non-GCC compilers use static
+   functions, which bloats the code but is good enough.  */
+
 #define INLINE _GL_INLINE
 #define EXTERN_INLINE _GL_EXTERN_INLINE
 #define INLINE_HEADER_BEGIN _GL_INLINE_HEADER_BEGIN
 #define INLINE_HEADER_END _GL_INLINE_HEADER_END
 
+/* To use the struct hack with N elements, declare the struct like this:
+     struct s { ...; t name[FLEXIBLE_ARRAY_MEMBER]; };
+   and allocate (offsetof (struct s, name) + N * sizeof (t)) bytes.  */
+#if 199901 <= __STDC_VERSION__
+# define FLEXIBLE_ARRAY_MEMBER
+#elif __GNUC__ && !defined __STRICT_ANSI__
+# define FLEXIBLE_ARRAY_MEMBER 0
+#else
+# define FLEXIBLE_ARRAY_MEMBER 1
+#endif
+
 /* Use this to suppress gcc's `...may be used before initialized' warnings. */
 #ifdef lint
 /* Use CODE only if lint checking is in effect.  */