decl.c (lookup_label): Build labels on the permanent obstack when building statement...

decl.c (lookup_label): Build labels on the permanent obstack when building statement trees.

	* decl.c (lookup_label): Build labels on the permanent obstack
	when building statement trees.  Don't build RTL for labels when
	building statement trees.
	* semantics.c (finish_goto_stmt): Use LABEL_DECLs even when
	building statement trees.
	(finish_label_stmt): Likewise.
	(expand_stmt): Adjust accordingly.
	* pt.c (tsubst_expr); Likewise.
	(do_decl_instantiation): Robustify.

From-SVN: r28918