glr.cc: simplifying the handling of parse/lex params

glr.cc: simplifying the handling of parse/lex params

The fact that glr.cc uses glr.c makes the handling of parse params
more complex, as the parser object of glr.cc must be passed to the
parse function of glr.c.  Yet not all the functions need access to
the parser object.

* data/glr.cc (b4_parse_param_wrap): New.
Use them.