cp-tree.def (TINST_LEVEL): Make it an 'x' node.

cp-tree.def (TINST_LEVEL): Make it an 'x' node.

	* cp-tree.def (TINST_LEVEL): Make it an 'x' node.
	* cp-tree.h (tinst_level_t): New tree type.
	(union lang_tree_node): Handle it.
	(TINST_LOCATION): New accessor macro.
	(make_tinst_level): New prototype.
	* cp-lang.c (cp_tree_size): Handle TINST_LEVEL.
	* decl.c (cp_tree_node_structure): Likewise.
	* error.c (print_instantiation_full_context): Use TINST_LOCATION.
	(print_instantiation_partial_context): Likewise.
	* pt.c (pop_tinst_level): Likewise.
	 (push_tinst_level): Use make_tinst_level.
	* tree.c (make_tinst_level): New function.
	(cp_walk_subtrees): Walk TINST_DECL for a TINST_LEVEL node.

From-SVN: r84977