parser: handle %locations as %define locations.

parser: handle %locations as %define locations.

	* src/getargs.h, src/getargs.c (locations_flag): Remove.
	* src/getargs.c, src/scan-code.l: Use muscle_percent_define_ensure
	to set "locations" to true.
	* src/output.c (prepare): Don't output "locations".
	* src/scan-gram.l (%locations): Handle it as a %<flag>.
	* src/parse-gram.y: It's no longer a token.
	Don't handle it.
	* data/bison.m4 (b4_locations_if): Define it with
	b4_percent_define_if_define.
	* data/c.m4, data/glr.cc: Adjust.