enable intrinsics for clangcl if -mssse3 is enabled.

BUG=451
TESTED=untested
R=harryjin@google.com

Review URL: https://webrtc-codereview.appspot.com/52699004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1427 16f28f9a-4ce2-e073-06de-1de4eb20be90

include/libyuv/row.h

@@ -158,8 +158,9 @@ extern "C" {
 #define HAS_SOBELYROW_SSE2
 #endif
 
-// The following are available on x64 Visual C:
-#if !defined(LIBYUV_DISABLE_X86) && defined (_M_X64) && !defined(__clang__)
+// The following are available on x64 Visual C and clangcl.
+#if !defined(LIBYUV_DISABLE_X86) && defined (_M_X64) && \
+    (!defined(__clang__) || defined(__SSSE3__))
 #define HAS_I422TOARGBROW_SSSE3
 #endif
 

source/row_win.cc

@@ -151,6 +151,7 @@ static YuvConstants SIMD_ALIGNED(kYuvJConstants) = {
 
 // 64 bit
 #if defined(_M_X64)
+#if defined(HAS_I422TOARGBROW_SSSE3)
 void I422ToARGBRow_SSSE3(const uint8* y_buf,
                          const uint8* u_buf,
                          const uint8* v_buf,
@@ -200,6 +201,7 @@ void I422ToARGBRow_SSSE3(const uint8* y_buf,
     width -= 8;
   }
 }
+#endif
 // 32 bit
 #else  // defined(_M_X64)
 #ifdef HAS_ARGBTOYROW_SSSE3