Unfortunately the autoconfig stuff has /unix hard
it and will only look for this file.
Thanks, guys, for the answer. I've got to admit that I'm disappointed.
If you have to decide, before the old system goes down, via a series of
moves or copies or hard links or whatever, which kernel you're going to use
the next time the system comes up, then it doesn't seem all that useful.
I guess if I build a kernel that just doesn't work at all, I can always
boot the old kernel far enough to get to single user mode where I can remove
the dud /unix, put the old one back, and then reboot. That's something.
Anyway, if that's the way it is, then that's the way it is :-) Thanks