GN: Build libvpx on ARM

BUILD.gn

Index: BUILD.gn
===================================================================
--- BUILD.gn	(revision 291843)
+++ BUILD.gn	(working copy)
@@ -171,13 +171,13 @@
 }
 
 # TOOD(hclam): NEON intrinsics are not building on GN yet.
-if (cpu_arch_full == "arm-neon-cpu-detect" && media_use_libvpx) {
-  static_library("libvpx_intrinsics_neon") {
-    configs += [ ":libvpx_config" ]
-    cflags = [ "-mfpu=neon", "-mfloat-abi=softfp" ]
-    sources = libvpx_srcs_arm_neon_cpu_detect_neon
-  }
-}
+#if (cpu_arch_full == "arm-neon-cpu-detect") {
+#  static_library("libvpx_intrinsics_neon") {
+#    configs += [ ":libvpx_config" ]
+#    cflags = [ "-mfpu=neon", "-mfloat-abi=softfp" ]
+#    sources = libvpx_srcs_arm_neon_cpu_detect_neon
+#  }
+#}
 
 static_library("libvpx") {
   if (!is_debug && is_win && is_official_build) {