make bootstrap changes

[Richard Kenner]

I'd like to ask that they be removed.

I just lost a night's run because doing a "make bootstrap" said there
was nothing to do.  The conditions on which files are tested to do
what is obscure and undocumented and every time I ask a question about how
to do what used to be a routine bootstrap restart or such, I don't get an
answer.  Some folks I've been working with have also expressed confusion
at the new procedures.

There is indeed a slight advantage in "make bootstrap" being able to
pick up in the middle if it was stopped, but that's something that
gets done far *less* often than copying files back and restarting, which is
now harder.

Why precisely, was this change done?  It seems to me to be causing a lot more
complications than the very slight simplification. 

Note that only developers will need to do either of the restarts, so
this change does not benefit GCC users, but complicates the Makefile.

Who is in favor of retaining this change?