clang/win/gn: Pass -msse flags to clang-cl.exe

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/arm.gni")
 import("//build/config/android/config.gni")
 import("//third_party/libvpx/libvpx_srcs.gni")
 import("//third_party/yasm/yasm_assemble.gni")
 
 if (is_posix && !is_mac) {
@@ skipping 71 matching lines @@
     sources = libvpx_srcs_x86_mmx
   } else if (current_cpu == "x64") {
     sources = libvpx_srcs_x86_64_mmx
   }
 }
 
 static_library("libvpx_intrinsics_sse2") {
   configs += [ ":libvpx_config" ]
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
-  if (!is_win) {
+  if (!is_win || is_clang) {
     cflags = [ "-msse2" ]
   }
   if (current_cpu == "x86") {
     sources = libvpx_srcs_x86_sse2
   } else if (current_cpu == "x64") {
     sources = libvpx_srcs_x86_64_sse2
   }
 }
 
 static_library("libvpx_intrinsics_ssse3") {
   configs += [ ":libvpx_config" ]
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
-  if (!is_win) {
+  if (!is_win || is_clang) {
     cflags = [ "-mssse3" ]
   }
   if (current_cpu == "x86") {
     sources = libvpx_srcs_x86_ssse3
   } else if (current_cpu == "x64") {
     sources = libvpx_srcs_x86_64_ssse3
   }
 }
 
 static_library("libvpx_intrinsics_sse4_1") {
   configs += [ ":libvpx_config" ]
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
-  if (!is_win) {
+  if (!is_win || is_clang) {
     cflags = [ "-msse4.1" ]
   }
   if (current_cpu == "x86") {
     sources = libvpx_srcs_x86_sse4_1
   } else if (current_cpu == "x64") {
     sources = libvpx_srcs_x86_64_sse4_1
   }
 }
 
 static_library("libvpx_intrinsics_avx2") {
@@ skipping 113 matching lines @@
   }
   if (is_android) {
     deps += [ "//third_party/android_tools:cpu_features" ]
   }
   if (current_cpu == "arm") {
     deps += [ ":libvpx_assembly_arm" ]
   }
 
   public_configs = [ ":libvpx_external_config" ]
 }