fix the compiling errors on MAC
0983cffc501e5279e7d9e9b2241b506cb332efcb

Index: source/test/testharness.h
--- source/test/testharness.h.orig
+++ source/test/testharness.h
@@ -73,7 +73,7 @@ class TestHarness (protected)
 #include <x86intrin.h>
 #elif ( !defined(__APPLE__) && defined (__GNUC__) && defined(__ARM_NEON__))
 #include <arm_neon.h>
-#elif defined(__GNUC__) && (!defined(__clang__) || __clang_major__ < 4)
+#else
 /* fallback for older GCC/MinGW */
 static inline uint32_t __rdtsc(void)
 {
