Is locore.s stable at the moment?  I'd like to redo and resubmit
my patches to omit all of the tests and branches on MMUTYPE
in kernels built for only one CPU type, but there's no point unless
locore.s is stable.

These patches produced what I thought was a detectably zippier
68040 system, although I didn't get a chance to do as much
testing as I might have liked, and didn't profile.

-s