port scale box filter sse2 to gcc

include/libyuv/scale_row.h

Index: include/libyuv/scale_row.h
diff --git a/include/libyuv/scale_row.h b/include/libyuv/scale_row.h
index e7594841b91a237cfa9c3c9f0a7b63de377814a1..30f3cdc571b715f084b875576d68aea4619a2daf 100644
--- a/include/libyuv/scale_row.h
+++ b/include/libyuv/scale_row.h
@@ -53,6 +53,7 @@ extern "C" {
 #define HAS_SCALEROWDOWN34_SSSE3
 #define HAS_SCALEROWDOWN38_SSSE3
 #define HAS_SCALEROWDOWN4_SSE2
+#define HAS_SCALEADDROW_SSE2
 #endif
 
 // The following are available for Visual C and clangcl 32 bit:
@@ -63,11 +64,6 @@ extern "C" {
 #define HAS_SCALEROWDOWN4_AVX2
 #endif
 
-// The following are available on Visual C:
-#if !defined(LIBYUV_DISABLE_X86) && defined(_M_IX86)
-#define HAS_SCALEADDROW_SSE2
-#endif
-
 // The following are available on Neon platforms:
 #if !defined(LIBYUV_DISABLE_NEON) && !defined(__native_client__) && \
     (defined(__ARM_NEON__) || defined(LIBYUV_NEON) || defined(__aarch64__))