Enable AVX2 optimizations in libvpx

libvpx_srcs_x86_intrinsics.gypi

Index: libvpx_srcs_x86_intrinsics.gypi
diff --git a/libvpx_srcs_x86_intrinsics.gypi b/libvpx_srcs_x86_intrinsics.gypi
index 95598f084c8155b396847e40307e4b2b4d683062..bd81bd9b03ea87d9d9131e4469e324eb73a5434d 100644
--- a/libvpx_srcs_x86_intrinsics.gypi
+++ b/libvpx_srcs_x86_intrinsics.gypi
@@ -95,5 +95,32 @@
         }],
       ],
     },
+    {
+      'target_name': 'libvpx_intrinsics_avx2',
+      'type': 'static_library',
+      'include_dirs': [
+        'source/config/<(OS_CATEGORY)/<(target_arch_full)',
+        '<(libvpx_source)',
+      ],
+      'sources': [
+        '<(libvpx_source)/vp9/common/x86/vp9_loopfilter_intrin_avx2.c',
+        '<(libvpx_source)/vp9/common/x86/vp9_subpixel_8t_intrin_avx2.c',
+        '<(libvpx_source)/vp9/encoder/x86/vp9_dct32x32_avx2.c',
+        '<(libvpx_source)/vp9/encoder/x86/vp9_dct_avx2.c',
+        '<(libvpx_source)/vp9/encoder/x86/vp9_error_intrin_avx2.c',
+        '<(libvpx_source)/vp9/encoder/x86/vp9_sad4d_intrin_avx2.c',
+        '<(libvpx_source)/vp9/encoder/x86/vp9_sad_intrin_avx2.c',
+        '<(libvpx_source)/vp9/encoder/x86/vp9_subpel_variance_impl_intrin_avx2.c',
+        '<(libvpx_source)/vp9/encoder/x86/vp9_variance_avx2.c',
+        '<(libvpx_source)/vp9/encoder/x86/vp9_variance_impl_intrin_avx2.c',
+      ],
+      'cflags': [ '-mavx2', ],
+      'xcode_settings': { 'OTHER_CFLAGS': [ '-mavx2' ] },
+      'msvs_settings': {
+        'VCCLCompilerTool': {
+          'EnableEnhancedInstructionSet': '3', # /arch:AVX
+        },
+      },
+    },
   ],
 }