GN: Fix skia build on mac, use -msse4.1 everywhere

Two issues with GN:
*) We need to set SK_BUILD_FOR_MAC on mac
*) On mac, the sse4 opts are built with -msse4.1 (which is what
GCC_ENABLE_SSE41_EXTENSIONS=YES expands to) not -msse4

and for consistency use -msse4.1 on linux as well.

Review URL: https://codereview.chromium.org/377833002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281969 0039d316-1c4b-4281-b951-d872f2087c98

skia/BUILD.gn

@@ -136,6 +136,10 @@ config("skia_config") {
       "USE_CHROMIUM_SKIA",
     ]
   }
+
+  if (is_mac) {
+    defines += [ "SK_BUILD_FOR_MAC" ]
+  }
 }
 
 # Internal-facing config for Skia library code.
@@ -556,7 +560,7 @@ source_set("skia_opts") {
     }
 
     if (is_linux || is_mac) {
-      cflags += [ "-msse4" ]
+      cflags += [ "-msse4.1" ]
     }
   } else if (cpu_arch == "arm") {
     sources = [

skia/skia_library_opts.gyp

@@ -225,7 +225,7 @@
       'conditions': [
         [ 'OS in ["linux", "freebsd", "openbsd", "solaris", "android"]', {
           'cflags': [
-            '-msse4',
+            '-msse4.1',
           ],
         }],
         [ 'OS == "mac"', {