The user should think of yypcontext fields as accessible only via
yypcontext_* functions. So let's rename yyexpected_tokens to reflect
that.
Let's _not_ rename yyreport_syntax_error, as the user may define this
function, and is not allowed to access directly the fields of
yypcontext_t: she *must* use the "accessors". This is comparable to
the case of C++/Java where the user defines
parser::report_syntax_error, not parser::context::report_syntax_error.
* data/skeletons/glr.c, data/skeletons/yacc.c (yyexpected_tokens):
Rename as...
(yypcontext_expected_tokens): this.
Adjust dependencies.