Port webrtc, webrtc-streamer to OpenWrt

[Bill Ross]

Hi;

I am (attempting to) port webrtc / webrtc-streamer to OpenWrt (x86_64), which involves:

- using OpenWrt sysroot

- adding custom CFLAGS, LDFLAGS

So far, based on the post below, it should be possible to fully specify build variables.

This post: https://bugs.chromium.org/p/chromium/issues/detail?id=595653 addresses build changes to set extra configuration

"This CL also adds the following optional build args that do pretty
much what you'd expect them to do:

  cros_target_ld, cros_target_extra_cflags, cros_target_extra_cppflags,
  cros_target_extra_cxx_flags, cros_target_extra_ldflags,
  cros_host_ar, cros_host_cc, cros_host_cxx, cros_host_ld,
  cros_host_is_clang, cros_host_extra_cflags, cros_host_extra_cppflags,
  cros_host_extra_cxx_flags, cros_host_extra_ldflags,
  cros_v8_snapshot_ar, cros_v8_snapshot_cc, cros_v8_snapshot_cxx,
  cros_v8_snapshot_ld, cros_v8_snapshot_extra_cflags,
  cros_v8_snapshot_extra_cppflags, cros_v8_snapshot_extra_cxx_flags,
  cros_v8_snapshot_extra_ldflags"

my generate arguments are:

	gn gen out/Release --args='is_debug=false \
                cros_target_ar="x86_64-openwrt-linux-gnu-ar" \
                cros_target_cc="x86_64-openwrt-linux-gnu-gcc" \
                cros_target_cxx="x86_64-openwrt-linux-gnu-g++" \
                target_sysroot="$(STAGING_DIR)" \
                use_custom_libcxx=false \
                is_clang=false \
                rtc_use_h264=true \
                ffmpeg_branding="Chrome" \
                rtc_include_tests=false \
                use_ozone=true \
                target_os="linux" \
                target_cpu="x64" \
                host_toolchain="//build/toolchain/cros:host" \
                cros_target_extra_ldflags="$(TARGET_LDFLAGS)" \
                cros_target_extra_cppflags="$(TARGET_CFLAGS)" \
                cros_target_extra_cflags="$(TARGET_CFLAGS)" \
                rtc_include_pulse_audio=false';

...BUT, the ldflags, cppflags, cflags are not appearing in any of the generated ninja files

Clearly, I am doing something wrong or, the post above is incorrect, or, I am missing the correct way to do this.

My first impulse was to just re-package the official binaries, but library version problems

root@SecureOffice:/tmp# ldd webrtc-streamer
./webrtc-streamer: /usr/lib/libasound.so.2: no version information available (required by ./webrtc-streamer)
./webrtc-streamer: /lib/libm.so.6: version `GLIBC_2.27' not found (required by ./webrtc-streamer)
./webrtc-streamer: /usr/lib/libstdc++.so.6: version `GLIBCXX_3.4.22' not found (required by ./webrtc-streamer)
        linux-vdso.so.1 (0x00007ffdce9fb000)
...other libs (found)

Any advice?
Regards;
Bill