dist .y and .c files reversed.
1. Move the .y.c and other assorted implicit rule overrides out of Makefile.inc
and into local Makefile's. The system Makefile (bsd.sys.mk) sets up .l.c and
.y.c rules so unless these come after all inclusions they just get ignored.
2. Add @true as the command for any of the rule overrides. Otherwise make
still bails complaining about not knowing how to build the requisite .c or
.h file.
This obviously wasn't tested before as it couldn't have worked as-is.
thorpej