Index: MicroBenchmarks/MemFunctions/main.cpp
===================================================================
--- MicroBenchmarks/MemFunctions/main.cpp
+++ MicroBenchmarks/MemFunctions/main.cpp
@@ -24,10 +24,19 @@
 
 #include "benchmark/benchmark.h"
 
+#ifndef __clang__
+// GCC does not allow attributes in function definition, placing in forward declaration instead.
+// Clang has the opposite behaviour.
+int RealMemCmp(const char *, const char *, size_t) __attribute__((no_builtin("memcmp")));
+#endif
+
 // This function prevents the compiler from interfering with `memcmp` and
 // makes sure the function is called.
 int RealMemCmp(const char *p, const char *q, size_t s)
-    __attribute__((no_builtin("memcmp"))) {
+#ifdef __clang__
+    __attribute__((no_builtin("memcmp")))
+#endif
+{
   return memcmp(p, q, s);
 }