Makefile: PARSER_OBJS is not used anymore

Signed-off-by: Jens Axboe <axboe@fb.com>
exp: update man page and HOWTO

Signed-off-by: Jens Axboe <axboe@fb.com>
Makefile: properly annotate LEX/YACC parts

Signed-off-by: Jens Axboe <axboe@fb.com>