PPC64 (done in Gentoo and version sdlmame0.130 here):

Code:
In src/emu/eigccppc.h, change all instances of bne-- to bne-
In src/osd/sdl/osinline.h, change all instances of bne-- to bne-

then with a terminal in the sdlmame directory just do
Code:
make BIGENDIAN=1 PTR64=1


Should work well smile