[Unix-jun72] UNIX V1 bootstrap

[James A. Markevitch]

I've ported the bootstrap stuff over the whole UNIX V1 build process.
(Note: it would be nice to have a V1 as, so that all of these hacks
we've been doing can go away).

I'll send out the .tar.gz under a separate e-mail, but it's small enough (10K)
and I don't know who's in which timezone, so somebody should be able
to commit it.

There are two versions included: one that copies the bootstrap into
the rf0.dsk image before running the simulator, and one that runs
native under V1.  Given that, if someone builds the kernel using
as under V1, they can use the usr/boot/msys command to install it
without leaving the simulation.

The good news is that you can use that to copy your test kernel into
the cold boot area and if it fails, can re-start the simulator from
the warm boot area and not lose any of your filesystem (assuming your
bad kernel didn't trash it, of course).

I also have a boot command, but haven't tested it yet.  It could be
used to reboot without leaving the simulation.  That's fine if your
kernel works, of course.

James Markevitch