libvpx: Pull from upstream

source/libvpx/build/make/configure.sh

 #!/bin/sh
 ##
 ##  configure.sh
 ##
 ##  This script is sourced by the main configure script and contains
 ##  utility functions and other common bits that aren't strictly libvpx
 ##  related.
 ##
 ##  This build system is based in part on the FFmpeg configure script.
 ##
@@ skipping 710 matching lines @@
 
   # PIC is probably what we want when building shared libs
   enabled shared && soft_enable pic
 
   # Minimum iOS version for all target platforms (darwin and iphonesimulator).
   IOS_VERSION_MIN="6.0"
 
   # Handle darwin variants. Newer SDKs allow targeting older
   # platforms, so use the newest one available.
   case ${toolchain} in
+    arm*-darwin*)
+      ios_sdk_dir="$(show_darwin_sdk_path iphoneos)"
+      if [ -d "${ios_sdk_dir}" ]; then
+        add_cflags  "-isysroot ${ios_sdk_dir}"
+        add_ldflags "-isysroot ${ios_sdk_dir}"
+      fi
+      ;;
     *-darwin*)
       osx_sdk_dir="$(show_darwin_sdk_path macosx)"
       if [ -d "${osx_sdk_dir}" ]; then
         add_cflags  "-isysroot ${osx_sdk_dir}"
         add_ldflags "-isysroot ${osx_sdk_dir}"
       fi
       ;;
   esac
 
   case ${toolchain} in
@@ skipping 55 matching lines @@
           soft_enable neon
           ;;
         armv7|armv7s)
           soft_enable neon
           # Only enable neon_asm when neon is also enabled.
           enabled neon && soft_enable neon_asm
           # If someone tries to force it through, die.
           if disabled neon && enabled neon_asm; then
             die "Disabling neon while keeping neon-asm is not supported"
           fi
-          soft_enable media
+          case ${toolchain} in
+            *-darwin*)
+              # Neon is guaranteed on iOS 6+ devices, while old media extensions
+              # no longer assemble with iOS 9 SDK
+              ;;
+            *)
+              soft_enable media
+          esac
           ;;
         armv6)
           soft_enable media
           ;;
       esac
 
       asm_conversion_cmd="cat"
 
       case ${tgt_cc} in
         gcc)
@@ skipping 592 matching lines @@
   # Prepare the PWD for building.
   for f in ${OOT_INSTALLS}; do
     install -D "${source_path}/$f" "$f"
   done
   fi
   cp "${source_path}/build/make/Makefile" .
 
   clean_temp_files
   true
 }