Bug 1516513 - Part 1. Add linux/aarch64 config to libvpx. r=jya

To use NEON on Linux/aarch64 and Android/aarch64, I would like to add it to
libvpx.  libvpx has a configuration as arm64-linux-gcc.

Differential Revision: https://phabricator.services.mozilla.com/D15400

--HG--
extra : moz-landing-system : lando

media/libvpx/generate_sources_mozbuild.sh

@@ -199,6 +199,7 @@ all_platforms="${all_platforms} --enable-multi-res-encoding --size-limit=8192x46
 all_platforms="${all_platforms} --disable-avx512"
 x86_platforms="--enable-postproc --enable-vp9-postproc --as=yasm"
 arm_platforms="--enable-runtime-cpu-detect --enable-realtime-only"
+arm64_platforms="--enable-realtime-only"
 
 gen_config_files linux/x64 "--target=x86_64-linux-gcc ${all_platforms} ${x86_platforms}"
 gen_config_files linux/ia32 "--target=x86-linux-gcc ${all_platforms} ${x86_platforms}"
@@ -210,6 +211,7 @@ gen_config_files win/mingw32 "--target=x86-win32-gcc ${all_platforms} ${x86_plat
 gen_config_files win/aarch64 "--target=aarch64-win64-vs12 ${all_platforms}"
 
 gen_config_files linux/arm "--target=armv7-linux-gcc ${all_platforms} ${arm_platforms}"
+gen_config_files linux/arm64 "--target=arm64-linux-gcc ${all_platforms} ${arm64_platforms}"
 
 gen_config_files generic "--target=generic-gnu ${all_platforms}"
 
@@ -238,6 +240,7 @@ gen_rtcd_header win/aarch64 aarch64
 
 
 gen_rtcd_header linux/arm armv7
+gen_rtcd_header linux/arm64 arm64
 
 gen_rtcd_header generic generic
 
@@ -271,6 +274,12 @@ make_clean
 make libvpx_srcs.txt target=libs $config > /dev/null
 convert_srcs_to_project_files libvpx_srcs.txt ARM
 
+echo "Generate ARM64 source list."
+config=$(print_config linux/arm64)
+make_clean
+make libvpx_srcs.txt target=libs $config > /dev/null
+convert_srcs_to_project_files libvpx_srcs.txt ARM64
+
 echo "Generate generic source list."
 config=$(print_config generic)
 make_clean

media/libvpx/moz.build

@@ -81,6 +81,11 @@ elif CONFIG['CPU_ARCH'] == 'aarch64' and CONFIG['OS_TARGET'] == 'WINNT':
     SOURCES += files['GENERIC_SOURCES']
     ASFLAGS += [ '-I%s/media/libvpx/config/win/aarch64/' % TOPSRCDIR ]
     LOCAL_INCLUDES += [ '/media/libvpx/config/win/aarch64/' ]
+elif CONFIG['CPU_ARCH'] == 'aarch64':
+    EXPORTS.vpx += files['ARM64_EXPORTS']
+    SOURCES += files['ARM64_SOURCES']
+    ASFLAGS += [ '-I%s/media/libvpx/config/linux/arm64/' % TOPSRCDIR ]
+    LOCAL_INCLUDES += [ '/media/libvpx/config/linux/arm64/' ]
 else:
     # Generic C-only configuration
     EXPORTS.vpx += files['GENERIC_EXPORTS']