add lint-specific hacks. at the same time, clean out a lot of ancient
cruft for old compilers and environments. there may be a 2nd round of
polishing after this; ok miod and others

Fix RCSID

Start factorizing luna88k and mvme88k common parts.
For now, include files only.

Initial commit for OpenBSD/luna88k, based on OpenBSD/mvme88k, NetBSD/luna68k and CMU Mach.