checkpoint:  input side code should work.  no output side yet.
Checkpoint wscons changes.
Add output-side support, using existing intvid/macvid support.
Update for wsdisplay/wscons support.
Make akbd_cngetc() work for the MRG-based driver.
We no longer have ite or grf in files.mac68k.
ite/grf is dead.  long live ite/grf!
ite/grf is dead, but wsdisplay will (at least partly) emulate them.
Update for ite/grf compatibility
Pull in opt_adb.h for ADB_DEBUG
First cut at grf emulation.  Neither GRFIOCMAP nor mmap'ing a wsdisplay device
work, though several other grf ioctls are properly emulated.
Rearrange console attachment slightly for sanity's sake.
Sync with main branch.
Sync with main branch.
UVM is no longer optional.
Add support for wscons as a console, using evil trickery.  To fix this
we'll have to revisit (and rip out) a bunch of things that happen before
the MMU is set up.

As a result, serial consoles now work again.
Refine the check for physical RAM segment sanity so that it stands a
chance of working on the IIci and IIsi.  (I wonder how this managed
to work after I put in code to sort the segments some time back...)
Sync with main branch.
Sync with main branch.
Sync with main branch.