@ruicunha
there's no need to rebuild anything. mame 0.78 set is trivial to obtain. what's more, it's a non-merged set so if you don't want all the clones, you can just delete them manually without breaking any of the ones you want to keep.

if it's only 400 roms you want it'll be quicker to just cut and paste those from the 0.78 set than to read our documentation ;)