Fixes for bootstrap handling

[Jeffrey A Law]

  In message < 9710011448.AA06981@lts.sel.alcatel.de >you write:
  > I just  tried to bootstrap  egcs-970924 for four  different systems in
  > parallel; of course, the  disk space was not  sufficient. To cope with
  > this  I made  the   appended changes which  simply  remove  the stage1
  > directory. They  also add support, if  comparing the stage2 and stage3
  > compilers yield differences.
  > 
  > Wed Oct  1 16:39:00 1997  Manfred Hollstein  (manfred@lts.sel.alcatel.de)
  > 
  > 	* Makefile.in (bootstrap): New goals bootstrap4, lean-bootstrap,
  > 	lean-bootstrap{2,3,4} added.
  > 	* gcc/Makefile.in (bootstrap): New goal lean-bootstrap added.
  > 	If actual goal is lean-bootstrap remove stage1 when appropriate.
  > 	(bootstrap2): Ditto.
  > 	(bootstrap3): Ditto.
  > 	(bootstrap4, lean-bootstrap4): New goal when building the stage4
  > 	compiler is necessary.
Note that we already have "bootstrap-lean", so if you could rework
your changes to fit in with the existing code it would be appreciated.

jeff