* class.c (check_field_decls): Only check C_TYPE_FIELDS_READONLY
	for class types.
	* cp-tree.h (C_TYPE_FIELDS_READONLY): Use a lang-specific bit
	rather than TYPE_LANG_FLAG_0.
	(TYPE_BUILT_IN): Remove.
	(TYPE_DEPENDENT_P): New macro.
	(TYPE_DEPENDENT_P_VALID): Likewise.
	(lang_type_class): Add fields_readonly.
	* decl.c (record_builtin_type): Don't set TYPE_BUILT_IN.
	* pt.c (dependent_type_p_r): New function, split out from ...
	(dependent_type_p): ... here.  Memoize results.
	* search.c (dependent_base_p): Use dependent_type_p, not
	uses_template_parms.
	* typeck.c (build_modify_expr): Only check C_TYPE_FIELDS_READONLY
	for class types.

From-SVN: r62143