* Makefile.in (fwprop.o): Include domwalk.h.
* fwprop.c: Include domwalk.h.
(reg_defs, reg_defs_stack): New.
(bitmap_only_bit_between): Remove.
(process_defs): New.
(process_uses): Use reg_defs and local_md instead of
bitmap_only_bit_between and local_rd.
(single_def_use_enter_block): New, from build_single_def_use_links.
(single_def_use_leave_block): New.
(build_single_def_use_links): Remove code moved to
single_def_use_enter_block, invoke domwalk.
(use_killed_between): Adjust comment.