third_party/libvpx: add BUILD.gn and friends
This CL adds build-related items to our fork of libvpx. The files that weren't
generated are adapted from Chromium, which arranged things a bit differently.
Specifically, the Chromium fork of libvpx is actually at
third_party/libvpx/source/libvpx and the relevant BUILD.gn stuff is in
third_party/libvpx. Our fork doesn't have this nested arrangement.
BUILD.gn - adapted from the Chromium version
README.fuchsia - adapted from Chromium's README.chromium and modified by
generate_gni.sh - generates and updates various files, adapted from the
lint_config.sh - a helper for generate_gni.sh, also adapted from Chromium
All other files added by this CL were generated by generate_gni.sh.
21 files changed