Enable prefetch and bswap buitins for clang.

src/core/bitmath_func.hpp

@@ -404,12 +404,12 @@ static inline T ROR(const T x, const uint8 n)
 	 */
 	static inline uint32 BSWAP32(uint32 x)
 	{
-#if !defined(__ICC) && defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4)  && __GNUC_MINOR__ >= 3))
+#if !defined(__ICC) && (defined(__GNUC__) || defined(__clang__))
 		/* GCC >= 4.3 provides a builtin, resulting in faster code */
 		return (uint32)__builtin_bswap32((int32)x);
 #else
 		return ((x >> 24) & 0xFF) | ((x >> 8) & 0xFF00) | ((x << 8) & 0xFF0000) | ((x << 24) & 0xFF000000);
-#endif /* defined(__GNUC__) */
+#endif /* __GNUC__ || __clang__ */
 	}
 
 	/**

src/stdafx.h

@@ -523,7 +523,7 @@ static inline void free(const void *ptr)
 #if defined(_MSC_VER)
 	#define INCLUDE_FOR_PREFETCH_NTA <xmmintrin.h>
 	#define PREFETCH_NTA(address) _mm_prefetch((const char *) (address), _MM_HINT_NTA);
-#elif defined(__GNUC__)
+#elif defined(__GNUC__) || defined(__clang__)
 	#define INCLUDE_FOR_PREFETCH_NTA "stdafx.h"
 	#define PREFETCH_NTA(address) __builtin_prefetch((const void *) (address), 0, 0);
 #else