* tree.h (TREE_SET_PERMANENT): New macro.  Document conditions
	under which TREE_PERMANENT will be set.
	* tree.c (make_node, copy_node, make_tree_vec, tree_cons,
	build1): Use TREE_SET_PERMANENT.
	* print-tree.c (print_node): Don't report value of
	TREE_PERMANENT if ggc_p is true.

	* c-common.c (c_get_alias_set): Don't use TREE_PERMANENT to
	decide whether to give a type a new alias set.
	* objc/objc-act.c (build_objc_string_object): Never copy the string.
	* tree.c (make_node): Set DECL_IN_SYSTEM_HEADER irrespective
	of value of 'obstack'.

	* f/com.c (ffecom_type_permanent_copy_): Delete unused function.
        (finish_decl): Don't change TREE_PERMANENT (DECL_INITIAL (decl)).

From-SVN: r32128