Upstream can now code generate the rtcd interface files directly from the aom_config.h header, so we no longer have to generate an intermediate file by running lint_config.sh. This also means we can remove the code for creating a temporary directory.
This changes generate_sources_mozbuild.sh to call generate_sources_mozbuild.py to generate sources.mozbuild and config files and removes the parts of the script that are no longer necessary.
This is a port of the libvpx scripts, themselves a port of Chromium's scripts to generate an external build description using hooks in the upstream configure and make scripts. The libaom library is a fork of libvpx so we can use a similar approach.
The upstream source is located in $(topsrc_dir)/third_party/aom but the build description and any patches are under the media directory with the other codecs, similar to how zlib works. Config files and headers generated by the upstream build system are also under $(topsrc_dir)/media/libaom/.
