There is no MUGEN implementation to Linux at all, other than that old beta version from Elecbyte(pc 32 bits).
Just a bunch of dead clones, and the best beat here is PainTown but, i saw no one trying to compile this on a Raspberry PI to see if it will work.
http://paintown.org/#/about
And, a libretro core of PainTown is still a work in progress(seems dead too).
https://forums.libretro.com/t/paintown-core/5792
