Fix locale memmem namespace (bug 17585).

Locale code, brought in by ISO C functions, calls memmem, which is not
an ISO C function.  This isn't an ISO C conformance bug, because all
mem* names are reserved, but glibc practice is not to rely on that
reservation (thus, memmem is only declared in string.h if __USE_GNU
even though ISO C would allow it to be declared unconditionally, for
example).  This patch changes that code to use __memmem.

Note: there are uses of memmem elsewhere in glibc that I didn't
change, although it may turn out some of those also need to use
__memmem.

Tested for x86_64 (testsuite, and that disassembly of installed shared
libraries is unchanged by this patch).

	[BZ #17585]
	* string/memmem.c [!_LIBC] (__memmem): Define to memmem.
	(memmem): Rename to __memmem and define as weak alias of
	__memmem.  Use libc_hidden_weak.
	(__memmem): Use libc_hidden_def.
	* include/string.h (__memmem): Declare.  Use libc_hidden_proto.
	* locale/findlocale.c (valid_locale_name): Use __memmem instead of
	memmem.

ChangeLog

@@ -1,5 +1,14 @@
 2014-11-12  Joseph Myers  <joseph@codesourcery.com>
 
+	[BZ #17585]
+	* string/memmem.c [!_LIBC] (__memmem): Define to memmem.
+	(memmem): Rename to __memmem and define as weak alias of
+	__memmem.  Use libc_hidden_weak.
+	(__memmem): Use libc_hidden_def.
+	* include/string.h (__memmem): Declare.  Use libc_hidden_proto.
+	* locale/findlocale.c (valid_locale_name): Use __memmem instead of
+	memmem.
+
 	[BZ #17582]
 	* libio/iofgets.c [weak_alias && !_IO_MTSAFE_IO]
 	(__fgets_unlocked): Add alias of _IO_fgets.  Use libc_hidden_def.

NEWS

@@ -11,7 +11,7 @@ Version 2.21
 
   6652, 12926, 14132, 14138, 14171, 15215, 15884, 17266, 17344, 17363,
   17370, 17371, 17411, 17460, 17475, 17485, 17501, 17506, 17508, 17522,
-  17555, 17570, 17571, 17572, 17573, 17574, 17582, 17583, 17584.
+  17555, 17570, 17571, 17572, 17573, 17574, 17582, 17583, 17584, 17585.
 
 * New locales: tu_IN, bh_IN.
 

include/string.h

@@ -90,6 +90,8 @@ extern char *__strsep_g (char **__stringp, const char *__delim);
 libc_hidden_proto (__strsep_g)
 libc_hidden_proto (strnlen)
 libc_hidden_proto (memmem)
+extern __typeof (memmem) __memmem;
+libc_hidden_proto (__memmem)
 libc_hidden_proto (__ffs)
 
 libc_hidden_builtin_proto (memchr)

locale/findlocale.c

@@ -79,7 +79,7 @@ valid_locale_name (const char *name)
     return 0;
   /* Directory traversal attempt.  */
   static const char slashdot[4] = {'/', '.', '.', '/'};
-  if (__glibc_unlikely (memmem (name, namelen,
+  if (__glibc_unlikely (__memmem (name, namelen,
 				  slashdot, sizeof (slashdot)) != NULL))
     return 0;
   if (namelen == 2 && __glibc_unlikely (name[0] == '.' && name [1] == '.'))

string/memmem.c

@@ -26,6 +26,7 @@
 
 #ifndef _LIBC
 # define __builtin_expect(expr, val)   (expr)
+# define __memmem	memmem
 #endif
 
 #define RETURN_TYPE void *
@@ -38,7 +39,7 @@
    if NEEDLE_LEN is 0, otherwise NULL if NEEDLE is not found in
    HAYSTACK.  */
 void *
-memmem (const void *haystack_start, size_t haystack_len,
+__memmem (const void *haystack_start, size_t haystack_len,
 	  const void *needle_start, size_t needle_len)
 {
   /* Abstract memory is considered to be an array of 'unsigned char' values,
@@ -73,6 +74,8 @@ memmem (const void *haystack_start, size_t haystack_len,
   else
     return two_way_long_needle (haystack, haystack_len, needle, needle_len);
 }
-libc_hidden_def (memmem)
+libc_hidden_def (__memmem)
+weak_alias (__memmem, memmem)
+libc_hidden_weak (memmem)
 
 #undef LONG_NEEDLE_THRESHOLD