Friend class name lookup 2/n, PR c++/14513, c++/15410
	* name-lookup.c (lookup_name_real): Simplify.
	(lookup_type_scope): Add SCOPE parameter.  Handle friend class
	lookup.
	* name-lookup.h (tag_scope): New enum type.
	(lookup_type_scope): Adjust declaration.
	* decl.c (lookup_and_check_tag, xref_tag, xref_tag_from_type):
	Change bool parameter GLOBALIZED to TAG_SCOPE parameter SCOPE.
	(start_enum): Likewise.  Add assertion test that NAME is
	IDENTIFIER_NODE.  Use anonymous name for dummy ENUMERAL_TYPE in
	case of error.
	* cp-tree.h (xref_tag, xref_tag_from_type): Adjust declarations.
	* parser.c (cp_parser_elaborated_type_specifier,
	cp_parser_class_head): Adjust call to xref_tag.
	* pt.c (lookup_template_class, instantiate_class_template):
	Likewise.
	* rtti.c (init_rtti_processing, build_dynamic_cast_1,
	tinfo_base_init, emit_support_tinfos): Likewise.

	* g++.dg/lookup/friend2.C: New test.
	* g++.dg/template/friend31.C: Likewise.

From-SVN: r91299