Delete obsolete macros

[Jeffrey A Law]

  In message < Pine.LNX.4.04.9911291738240.29558-100000@pathia.cygnus.co.uk >you 
write:
  > OVERLAPPING_REGNO_P and INSN_CLOBBERS_REGNO_P haven't been used in years
  > and are too nasty to keep.
  > 
  > Bernd
  > 
  > 	* cse.c (FIXED_REGNO_P): Delete tests for OVERLAPPING_REGNO_P.
  > 	* global.c (global_alloc): Delete [OVERLAPPING_REGNO_P] code.
  > 	* reload.c (find_dummy_reload): Likewise.
  > 	(find_equiv_reg): Likewise; also for INSN_CLOBBERS_REGNO_P.
  > 	* reload1.c (reload_as_needed): Likewise.
  > 	* stupid.c (stupid_find_reg): Likewise.
  > 	* tm.texi (Obsolete Register Macros): Delete section.
  > 	* gmicro.h: Remove all traces of the two macros.
  > 	* i386.h: Likewise.
  > 	* m88k.h: Likewise.
  > 	* mips.h: Likewise.
Kill 'em.  We should have deleted this stuff years ago :-)

jeff