If you're not experienced with c++ there's probably not so much you can help with. The DS can be a fun platform to work with, but porting a game to a handheld with such limited resources can be complicated. Thanks though.
Anyway... I've compiled an executable. I did disable the opengl stuff when compiling in ds mode. It displays the "loading..." text on the top screen, though it's extremely squished and unreadable. But there's output on the other screen. Here's what I've got so far:
NDS_SetVideoMode
Setting mode 640x4000 (ndsmode 4)
Loading...
Loading ruleset...
std::bad_alloc
bad_alloc means it ran out of memory. The ds has a measly 4 megabytes of memory, and the executable itself has to fit in there. I knew this would be a problem, which is why I compiled everything with the -Os flag (optimize for size). I have an ez-flash 3in1 with 16 extra megabytes of ram, which might be enough. Though I haven't figured out yet how to use this extra memory with malloc() and new.
Oh, and I checked the memory used by openxcom on my computer. 20 megabytes in the main menu. Basically, if this does work, it will probably require the ram expansion.