Build x264 for Android arm64

export NDK=$ANDROID_NDK
export PREBUILT_ARM64=$NDK/toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64
export X264_ANDROID_PREFIX_ARM64=$X264_BUILD_ROOT/output/arm64

function build_arm64 {
    ./configure \
    --prefix=$X264_ANDROID_PREFIX_ARM64 \
    --enable-static \
    --enable-pic \
    --host=aarch64-linux \
    --cross-prefix=$PREBUILT_ARM64/bin/aarch64-linux-android- \
    --sysroot=$PLATFORM_ARM64

    make clean
    make
    make install

    echo "Build libx264 arm64 Finished !!!"
}

If you compile ffmpeg with libx264.a , you MUST use same NDK toolchains. Otherwise cannot link to libx264.a