fix endian problems in pattern copy
CopyBlock8b() was over-using memcpy() of 16b values.
@@ -933,7 +933,11 @@ static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
#endif
break;
case 2:
+#if !defined(WORDS_BIGENDIAN)
memcpy(&pattern, src, sizeof(uint16_t));
+#else
+ pattern = ((uint32_t)src[0] << 8) | src[1];
+#endif
#if defined(__arm__) || defined(_M_ARM)
pattern |= pattern << 16;
#elif defined(WEBP_USE_MIPS_DSP_R2)
