use vectorsize on clangcl

include/libyuv/row.h

Index: include/libyuv/row.h
diff --git a/include/libyuv/row.h b/include/libyuv/row.h
index 3028513e5a5e21b02511e3fa9a172c74db3bb570..b9ea5a84258a274d76e593a8c158f3460fbf8d4c 100644
--- a/include/libyuv/row.h
+++ b/include/libyuv/row.h
@@ -372,7 +372,7 @@ extern "C" {
 #endif
 #endif
 
-#if defined(_MSC_VER) && !defined(__CLR_VER)
+#if defined(_MSC_VER) && !defined(__CLR_VER) && !defined(__clang__)
 #define SIMD_ALIGNED(var) __declspec(align(16)) var
 #define SIMD_ALIGNED32(var) __declspec(align(64)) var
 typedef __declspec(align(16)) int16 vec16[8];
@@ -387,7 +387,7 @@ typedef __declspec(align(32)) int8 lvec8[32];
 typedef __declspec(align(32)) uint16 ulvec16[16];
 typedef __declspec(align(32)) uint32 ulvec32[8];
 typedef __declspec(align(32)) uint8 ulvec8[32];
-#elif defined(__GNUC__) && !defined(__pnacl__)
+#elif !defined(__pnacl__) && (defined(__GNUC__) || defined(__clang__))
 // Caveat GCC 4.2 to 4.7 have a known issue using vectors with const.
 #define SIMD_ALIGNED(var) var __attribute__((aligned(16)))
 #define SIMD_ALIGNED32(var) var __attribute__((aligned(64)))