commit 602f80ec8b966cfad3b61914cbe14ee606cedf6e
Author: Siddhesh Poyarekar <siddhesh@redhat.com>
Date:   Tue Sep 16 22:16:01 2014 +0530

    Make __extern_always_inline usable on clang++ again
    
    The fix for BZ #17266 (884ddc5081278f488ef8cd49951f41cfdbb480ce)
    removed changes that had gone into cdefs.h to make
    __extern_always_inline usable with clang++.  This patch adds back
    support for clang to detect if GNU inlining semantics are available,
    this time without breaking the gcc use case.  The check put here is
    based on the earlier patch and assertion[1] that checking if
    __GNUC_STDC_INLINE__ or __GNUC_GNU_INLINE__ is defined is sufficient
    to determine that clang++ suports GNU inlining semantics.
    
    Tested with a simple program that builds with __extern_always_inline
    with the patch and fails compilation without it.
    
     #include <stdio.h>
     #include <sys/cdefs.h>
    
    extern void foo_alias (void) __asm ("foo");
    
    __extern_always_inline void
    foo (void)
    {
      puts ("hi oh world!");
      return foo_alias ();
    }
    
    void
    foo_alias (void)
    {
      puts ("hell oh world");
    }
    
    int
    main ()
    {
      foo ();
    }
    
    [1] https://sourceware.org/ml/libc-alpha/2012-12/msg00306.html
    
    	[BZ #17266]
    	* misc/sys/cdefs.h: Define __extern_always_inline for clang
    	4.2 and newer.

commit 884ddc5081278f488ef8cd49951f41cfdbb480ce
Author: Siddhesh Poyarekar <siddhesh@redhat.com>
Date:   Tue Sep 16 14:08:48 2014 +0530

    Revert to defining __extern_inline only for gcc-4.3+ (BZ #17266)
    
    The check for only __GNUC_STDC_INLINE__ and __GNUC_GNU_INLINE__ may
    not be sufficient since those flags were added during initial support
    for C99 inlining semantics.  There is also a problem with always
    defining __extern_inline and __extern_always_inline, since it enables
    inline wrapper functions even when GNU inlining semantics are not
    guaranteed.  This, along with the possibility of such wrappers using
    redirection (btowc for example) could result in compiler generating an
    infinitely recusrive call to the function.
    
    In fact it was such a recursion that led to this code being written
    the way it was; see:
    
    https://bugzilla.redhat.com/show_bug.cgi?id=186410
    
    The initial change was to fix bugs 14530 and 13741, but they can be
    resolved by checking if __fortify_function and/or
    __extern_always_inline are defined, as it has been done in this patch.
    In addition, I have audited uses of __extern_always_inline to make
    sure that none of the uses result in compilation errors.
    
    There is however a regression in this patch for llvm, since it reverts
    the llvm expectation that __GNUC_STDC_INLINE__ or __GNUC_GNU_INLINE__
    definition imply proper extern inline semantics.
    
    2014-09-16  Siddhesh Poyarekar  <siddhesh@redhat.com>
    	    Jakub Jelinek  <jakub@redhat.com>
    
    	[BZ #17266]
    	* libio/stdio.h: Check definition of __fortify_function
    	instead of __extern_always_inline to include bits/stdio2.h.
    	* math/bits/math-finite.h [__USE_XOPEN || __USE_ISOC99]: Also
    	check if __extern_always_inline is defined.
    	[__USE_MISC || __USE_XOPEN]: Likewise.
    	[__USE_ISOC99] Likewise.
    	* misc/sys/cdefs.h (__fortify_function): Define only if
    	__extern_always_inline is defined.
    	[!__cplusplus || __GNUC_PREREQ (4,3)]: Revert to defining
    	__extern_always_inline and __extern_inline only for g++-4.3
    	and newer or a compatible gcc.

diff --git glibc-2.17-c758a686/libio/stdio.h glibc-2.17-c758a686/libio/stdio.h
index d8c0bdb..1f4f837 100644
--- glibc-2.17-c758a686/libio/stdio.h
+++ glibc-2.17-c758a686/libio/stdio.h
@@ -932,7 +932,7 @@ extern void funlockfile (FILE *__stream) __THROW;
 #ifdef __USE_EXTERN_INLINES
 # include <bits/stdio.h>
 #endif
-#if __USE_FORTIFY_LEVEL > 0 && defined __extern_always_inline
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
 # include <bits/stdio2.h>
 #endif
 #ifdef __LDBL_COMPAT
diff --git glibc-2.17-c758a686/math/bits/math-finite.h glibc-2.17-c758a686/math/bits/math-finite.h
index aa755de..0656645 100644
--- glibc-2.17-c758a686/math/bits/math-finite.h
+++ glibc-2.17-c758a686/math/bits/math-finite.h
@@ -251,7 +251,8 @@ extern long double __REDIRECT_NTH (lgammal_r, (long double, int *),
 # endif
 #endif
 
-#if defined __USE_MISC || defined __USE_XOPEN || defined __USE_ISOC99
+#if ((defined __USE_MISC || defined __USE_XOPEN || defined __USE_ISOC99) \
+     && defined __extern_always_inline)
 /* lgamma.  */
 __extern_always_inline double __NTH (lgamma (double __d))
 {
@@ -284,7 +285,8 @@ __extern_always_inline long double __NTH (lgammal (long double __d))
 # endif
 #endif
 
-#if defined __USE_MISC || defined __USE_XOPEN
+#if ((defined __USE_MISC || defined __USE_XOPEN) \
+     && defined __extern_always_inline)
 /* gamma.  */
 __extern_always_inline double __NTH (gamma (double __d))
 {
@@ -422,7 +424,7 @@ extern long double __REDIRECT_NTH (sqrtl, (long double), __sqrtl_finite);
 # endif
 #endif
 
-#ifdef __USE_ISOC99
+#if defined __USE_ISOC99 && defined __extern_always_inline
 /* tgamma.  */
 extern double __gamma_r_finite (double, int *);
 __extern_always_inline double __NTH (tgamma (double __d))
diff --git glibc-2.17-c758a686/misc/sys/cdefs.h glibc-2.17-c758a686/misc/sys/cdefs.h
index 04db956..01e81ba 100644
--- glibc-2.17-c758a686/misc/sys/cdefs.h
+++ glibc-2.17-c758a686/misc/sys/cdefs.h
@@ -131,7 +131,6 @@
 /* Fortify support.  */
 #define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
 #define __bos0(ptr) __builtin_object_size (ptr, 0)
-#define __fortify_function __extern_always_inline __attribute_artificial__
 
 #if __GNUC_PREREQ (4,3)
 # define __warndecl(name, msg) \
@@ -319,8 +318,17 @@
 #endif
 
 /* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
-   inline semantics, unless -fgnu89-inline is used.  */
-#if (!defined __cplusplus || __GNUC_PREREQ (4,3)) && defined __GNUC__
+   inline semantics, unless -fgnu89-inline is used.  Using __GNUC_STDC_INLINE__
+   or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions
+   older than 4.3 may define these macros and still not guarantee GNU inlining
+   semantics.
+
+   clang++ identifies itself as gcc-4.2, but has support for GNU inlining
+   semantics, that can be checked fot by using the __GNUC_STDC_INLINE_ and
+   __GNUC_GNU_INLINE__ macro definitions.  */
+#if (!defined __cplusplus || __GNUC_PREREQ (4,3) \
+     || (defined __clang__ && (defined __GNUC_STDC_INLINE__ \
+			       || defined __GNUC_GNU_INLINE__)))
 # if defined __GNUC_STDC_INLINE__ || defined __cplusplus
 #  define __extern_inline extern __inline __attribute__ ((__gnu_inline__))
 #  define __extern_always_inline \
@@ -329,13 +337,10 @@
 #  define __extern_inline extern __inline
 #  define __extern_always_inline extern __always_inline
 # endif
-#elif defined __GNUC__ /* C++ and GCC <4.3.  */
-# define __extern_inline extern __inline
-# define __extern_always_inline \
-  extern __always_inline
-#else /* Not GCC.  */
-# define __extern_inline  /* Ignore */
-# define __extern_always_inline /* Ignore */
+#endif
+
+#ifdef __extern_always_inline
+# define __fortify_function __extern_always_inline __attribute_artificial__
 #endif
 
 /* GCC 4.3 and above allow passing all anonymous arguments of an