Thanks guys! I dunno why I had problems before, but I played with the compiler tools some more, and I was able to compile MameCE3 with a lot of errors. I got a lot of them out, but I'm stuck on 5 or 6 linker errors.
(I actually started compiling MameBoy, but gave up on that, and switched to MameCE3.)
I'll play with it some more, but it's having trouble with ordinary library functions such as "isgraph" and "strrchr".
All my other problems I have hacked around. :-) I hope I didn't hack too much. ;-) Maybe 30% of the errors were due to the absense of a library using the "HPC Pro" option instead of the "Palm" compile option. I don't know if this is important or not, but I bet I'll have to come back to that!
I guess the plan now is that if I get this to run, then I'll be asking where to look for the resolution-related parts to change, as I've not seen anything obvious so far.