Concentrate compiler dependencies to compiler.h; make sure compiler.h
is included first in every .c file (since some prototypes may depend
on the presence of feature request macros.)
Actually use the conditional inclusion of various functions (totally
broken in previous releases.)
Instead of returning -1 from nasm_token_hash, set tv->t_type to
TOKEN_ID and return TOKEN_ID, since that's what stdscan.c wants to do
with it anyway. This allows us to simply tailcall nasm_token_hash().
Finish the perfect hash tokenizer, and actually enable it.
Move stdscan() et al to a separate file, since it's not needed in any
of the clients of nasmlib other than nasm itself.
Run make alldeps.
