Fix libvpx's gyp for enabling AVX instructions with MSVC and clang-cl

third_party/libvpx_new/generate_gypi.sh

Index: third_party/libvpx_new/generate_gypi.sh
diff --git a/third_party/libvpx_new/generate_gypi.sh b/third_party/libvpx_new/generate_gypi.sh
index 93ffdecac1630a4eb16dd242cb29f5108b15c762..d650e8d06c2b4bf37e204864bdd8b869107ff24f 100755
--- a/third_party/libvpx_new/generate_gypi.sh
+++ b/third_party/libvpx_new/generate_gypi.sh
@@ -169,7 +169,7 @@ function write_target_definition {
   if [[ -z $DISABLE_AVX && $4 == avx ]]; then
   echo "      'msvs_settings': {" >> "$2"
   echo "        'VCCLCompilerTool': {" >> "$2"
-  echo "          'EnableEnhancedInstructionSet': '4', # /arch:AVX" >> "$2"
+  echo "          'EnableEnhancedInstructionSet': '3', # /arch:AVX" >> "$2"
   echo "        }," >> "$2"
   echo "      }," >> "$2"
   fi