[PATCH, testsuite] Fix gcc.dg/memcmp-1.c for targets using __USER_LABEL_PREFIX__

[Iain Sandoe]

Hi,

The test fails on Darwin (and presumably on other _U_L_P_ targets) because the 
asm-specified symbol isn’t found at link time.

OK for trunk?

thanks
Iain

gcc/testsuite:

        * gcc.dg/memcmp-1.c (lib_memcmp): Apply __USER_LABEL_PREFIX__.
        (lib_strncmp): Likewise.

diff --git a/gcc/testsuite/gcc.dg/memcmp-1.c b/gcc/testsuite/gcc.dg/memcmp-1.c
index a79db51..619cf9b 100644
--- a/gcc/testsuite/gcc.dg/memcmp-1.c
+++ b/gcc/testsuite/gcc.dg/memcmp-1.c
@@ -8,8 +8,13 @@
 #include <string.h>
 #include <stdint.h>
 
-int lib_memcmp(const void *a, const void *b, size_t n) asm("memcmp");
-int lib_strncmp(const char *a, const char *b, size_t n) asm("strncmp");
+#define STR1(X) #X
+#define STR2(X) STR1(X)
+
+int lib_memcmp(const void *a, const void *b, size_t n)
+ asm(STR2(__USER_LABEL_PREFIX__) "memcmp");
+int lib_strncmp(const char *a, const char *b, size_t n)
+ asm(STR2(__USER_LABEL_PREFIX__) "strncmp");
 
 #ifndef NRAND
 #ifdef TEST_ALL