After a dozen or so "e-mail debugging sessions" and code exchanges with
Juergen Hannken-Illjes, I'm confident to say that the `Fujitsu turbosparc'
support for the Sparcstation 5/170 seems to be in pretty good shape now.

The CPU attach code will detect a cloaked turbosparc (the "featurefull"
SS5/170 PROM luckily leaves enough hints lying about) and puts it
back into native mode. Operation in native mode isn't much different
from the uSparcII processor in SS4s and previous SS5s, though it
managed to expose a few glitches in the existing code.

Many thanks to Juergen and to Geoff Adams for locking up their machines
while this was worked out.

-pk