Amusingly enough, glr2.cc still had its core function, yyparse, being
a free function instead of a member function.
* data/skeletons/glr2.cc (yyparse): Remove this free function called
from yyparser::parse. Inline its body into...
(yyparser::parse): this member function.
This requires moving a bit the yychar, etc. macros.
Access to token can be simplified (the
b4_namespace_ref::b4_parser_class prefix is no longer needed).