I'm not sure that the mismatch between refdef_t and the assembly defines
was a problem (many fields unused), but the main problem was due to
execute permission on the pages: one chunk of asm was in the data
section, and the patched code was not marked as being executable (due to
such a thing not existing when quake was written).
All of the nastiness is hidden in bspfile.c (including the old bsp29
specific data types). However, the conversions between bsp29 and bsp2 are
implemented but not yet hooked up properly. This commit just gets the data
structures in place and the obvious changes necessary to the rest of the
engine to get it to compile, plus a few obvious "make it work" changes.