After making `ffmpeg` point to the latest `ffmpeg_4`, all packages that
used `ffmpeg` without requiring a specific version now use ffmpeg_3
explicitly so they shouldn't change.
The patches do no longer apply on-top of the pjsip version we provice.
One of the maintainers (@Radvendii @olynch) should have a look what can
be done about this.
The build has been failing since 2017-07-31…