Is there interest in a zero networking build config?

Hi, I have a patch locally to disable everything networking related, if you think that's a good thing I can try to upstream it as a build option.

It needs changes to the muxer/demuxer lists, which are included by other files so you can't just have two of them, not sure how to deal with that nicely from build.zig (add an ifdef? then you have to keep redoing that when you update ffmpeg)