Adjust yacc builds to support the original yacc (as opposed to bison)

yacc doesn't support the arguments we've been giving to bison. byacc was
also tested.

.gitignore

@@ -15,11 +15,11 @@ Makefile
 /config_util
 /configure
 /executecmd
-/gram.c
-/gram.h
+/gram.tab.c
+/gram.tab.h
 /kbdlexer.c
-/kbdmodule.c
-/kbdmodule.h
+/kbdmodule.tab.c
+/kbdmodule.tab.h
 /lex.c
 /ppmtoinfo
 /requestchoice