undone by rev 1.7:
>redo pmax/include/reg.h
>so that the definitions needed by locore.S are in a separate file,
>pmax/include/regnum.h.
* Add explicit `#include <mips/regnum.h>' where symbolic offsets
into a mips trapframe or struct reg are used..
* define PT_GETREGS and PT_SETREGS in pmax/include/ptrace.h
* Flesh out the stubs in pmax/pmax/process_machdep.c to handle
those requests.
* Now that "struct reg" is actually used, remove the bogus
#ifdef LANGUAGE_C around its definition, and redo pmax/include/reg.h
so that the definitions needed by locore.S are in a separate file,
pmax/include/regnum.h.
* update locore.S to match.