To run the former MESS stuff in MAME you basically need to know 2 things the name that MAME knows the system by and the type of media. You would just add those two things to the command line. So for example Turbo Grafx is tg16 -cart PCEngine would be pcengine -cart. Now using the CD portion of this system is different and from what I've read requires a different command line pointing the bios to the actual file name of the CD game so while usually the basic command of system + media type doesn't always work.