Doesn't need to be modded with like resistors soldered on and stuff like that... just get a RetroTink board to slap on top of it:
http://retrotink.com/
Then you literally only have to copy and paste in a couple lines of code into the config.txt and you're done. I mean, there's TONS of finer points on setting up the RetroPie, Lakka, or whatever emulation software you put on it, but that's the quick gist of it.