Test for SSE3 suppport before using pshufb.

snappy.cc

@@ -183,7 +183,7 @@ inline char* IncrementalCopy(const char* src, char* op, char* const op_limit,
 
   // Handle the uncommon case where pattern is less than 8 bytes.
   if (SNAPPY_PREDICT_FALSE(pattern_size < 8)) {
-#if SNAPPY_HAVE_SSE2
+#if defined __SSSE3__
     // Load the first eight bytes into an 128-bit XMM register, then use PSHUFB
     // to permute the register's contents in-place into a repeating sequence of
     // the first "pattern_size" bytes.