I never liked it, but with C2x coming out, it's best to handle bools
properly. I haven't gone through all the uses of int as bool (I'll leave
that for fixing when I encounter them), but this gets QF working with
both c2x (really, gnu2x because of raw strings).
It was added only because FitzQuake used it in its pre-bsp2 large-map
support. That support has been hidden in bspfile.c for some time now.
This doesn't gain much other than having one less type to worry about.
Well tested on Conflagrant Rodent (the map that caused the need for
mclipnode_t in the first place).
