some new debugging functions

[Jeffrey A Law]

  In message < 20000216135237.B14680@wolery.cumb.org >you write:
  > I found these to be rather useful while chasing a flow bug.
  > 
  > zw
  > 
  > 	* flow.c (dump_regset, debug_regset, dump_bb, debug_bb,
  > 	debug_bb_n): New functions.
  > 	(dump_flow_info, print_rtl_with_bb): Use dump_regset.
  > 	* basic-block.h: Prototype new functions.
This is fine.  Please install.

Thanks,
jeff