* data/yacc.c (yyparse): Wrap the final return from yyparse inside YYID

* data/yacc.c (yyparse): Wrap the final return from yyparse inside YYID
to make sure that YYID will never be unused.  This fixes a 'make
maintainer-check' failure caused by the recent changes to the 'Trivial
grammars' test case, which caused g++ 4.1.0 to complain that YYID was
not used.
* data/glr.c (yyparse): Wrap yyparse's return inside YYID just in case.