lalr1.cc: get rid of yyparse's yystate.

lalr1.cc: get rid of yyparse's yystate.

yystate and yystack_[0].state are equal, keep only the latter.
The former was also used as a temporary variable to compute the
post-reduction state.  Move this computation into an auxiliary
function.

	* data/glr.c (yyLRgotoState): Fuse variable definition and first
	assignment.
	* data/lalr1.cc (yy_lr_goto_state_): New.
	(yyparse): Use it.
	Replace remaining uses of yystate by yystate_[0].state.
	Remove the former.