>> If you look at what MAMEdev's actually shipping, you'll see that we've been converting the entire codebase from fake OO with macros to real OO in real C++ over the last 2 years. MESS is actually farther ahead on this than MAME, but the core is ready in either case. This has enabled a whole slew of good things to happen, including the combined build under discussion and much better separation between chip emulations and drivers.
I see Aaron's re-write of drawgfx, it's finally free of that self recursing noodle soup, but looking a bit more into the whole re-write thing I see some kind of pointless effort to make MAME "modern" (for some future OS, as Derrick says). You know, having 17 bits precision stored in 32 bits based on funny assumption it might become "standard", one day. Kind of stuff I'd call "unnecessary bloat".
So, anyway, are you saying all the #IFDEFs are going to be gone? MESS actually separated to its own files rather than mingling within MAME core? If so, I applaud that and I'd be glad to help, just shine the sign up in the sky.
By the way, I've sent you link to my Android MAME build, you have to try "Crazy Scoreboard" and "Crazy Tilt"... super-cool, if I may say so.