MurmurHash3: actually inline functions

"__attribute__((always_inline))" does not replace "inline" and they
still need to be used together. This fixes "always_inline function
might not be inlinable [-Wattributes]" warning in gcc 4.7
Idea-from-patch-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

src/shared/MurmurHash3.c

@@ -29,7 +29,7 @@
 
 #else	// defined(_MSC_VER)
 
-#define	FORCE_INLINE __attribute__((always_inline))
+#define	FORCE_INLINE inline __attribute__((always_inline))
 
 static inline uint32_t rotl32 ( uint32_t x, int8_t r )
 {