gn win: Don't add linux-style cflags

media/base/BUILD.gn

Index: media/base/BUILD.gn
diff --git a/media/base/BUILD.gn b/media/base/BUILD.gn
index fe75b85562be625d6e0da00bb67d6252ae7f530d..6d6ee56879d5fbd7d0935ef19715e4ead7390395 100644
--- a/media/base/BUILD.gn
+++ b/media/base/BUILD.gn
@@ -352,7 +352,9 @@ if (cpu_arch == "x86" || cpu_arch == "x64") {
   source_set("media_mmx") {
     sources = [ "simd/filter_yuv_mmx.cc" ]
     configs += [ "//media:media_config" ]
-    cflags = [ "-mmmx" ]
+    if (!is_win) {
+      cflags = [ "-mmmx" ]

[scottmg, 2014/08/13 23:25:35]

This is a bit tricky, 'cflags' is ignored in gyp on windows so there's likely
other places that will do incorrect conversions like this from .gyp files.

[DaleCurtis, 2014/08/14 00:23:26]

Does msvc require a similar setting?

+    }
   }
 
   source_set("media_sse2") {
@@ -362,7 +364,9 @@ if (cpu_arch == "x86" || cpu_arch == "x64") {
       "simd/filter_yuv_sse2.cc",
     ]
     configs += [ "//media:media_config" ]
-    cflags = [ "-msse2" ]
+    if (!is_win) {
+      cflags = [ "-msse2" ]
+    }
   }
 
   import("//third_party/yasm/yasm_assemble.gni")