As already mentioned, xvid_encraw was rather merely a usage demonstration than a production application. The AVI muxer does not even create OpenDML, bad for target sizes >2 GB.
Talented developers are possibly able to create a really useful encoder application based on this. But ... how many people do still need MPEG4-ASP these days? So, how much efforts is such a tool worth now?
Anyway, MABS now uses its own fork:
https://github.com/m-ab-s/xvid.git ... and AFAIK, MABS also supports private local patches in its profile system.
PS: MP4Box was recently fixed to support multiplexing raw MPEG4-ASP to MP4 again.