add ObjC* class, category and protocol attribute parsers

add ObjC* class, category and protocol attribute parsers

gcc/c-family:

	* c-common.h (objc_start_class_interface): Adjust prototype.
	(objc_start_category_interface): Likewise.
	(objc_start_protocol): Likewise.
	* stub-objc.c (objc_start_protocol): Adjust for extra argument.
	(objc_start_class_interface): Likewise.
	(objc_start_category_interface): Likewise.

gcc/objc:

	* objc-act.c (objc_start_class_interface): Handle and ignore attributes.
	(objc_start_category_interface): Likewise.
	(objc_start_protocol): Likewise.

gcc/cp:

	* parser.c (cp_parser_objc_valid_prefix_attributes): New.
	(cp_parser_declaration): Parse prefix attributes for ObjC++.
	(cp_parser_objc_protocol_declaration): Handle attributes.
	(cp_parser_objc_class_interface): Likewise.
	(cp_parser_objc_declaration): Likewise.

gcc:

	* c-parser.c (c_parser_objc_class_definition): Adjust prototype.
	(c_parser_objc_protocol_definition): Likewise.
	(c_parser_external_declaration): Provide dummy attribute arguments.
	(c_parser_declaration_or_fndef): Parse prefix attributes for ObjC.
	(c_parser_objc_class_definition): Handle attributes.
	(c_parser_objc_protocol_definition): Likewise.

gcc/testsuite:

	* objc.dg/attributes: New.
	* objc.dg/attributes/attributes.exp: New.
	* objc.dg/attributes/class-attribute-1.m: New.
	* objc.dg/attributes/class-attribute-2.m: New
	* objc.dg/attributes/categ-attribute-1.m: New
	* objc.dg/attributes/categ-attribute-2.m: New
	* objc.dg/attributes/proto-attribute-1.m: New

	* obj-c++.dg/attributes: New.
	* obj-c++.dg/attributes/attributes.exp: New
	* obj-c++.dg/attributes/class-attribute-1.mm: New
	* obj-c++.dg/attributes/class-attribute-2.mm: New
	* obj-c++.dg/attributes/categ-attribute-1.mm: New
	* obj-c++.dg/attributes/categ-attribute-2.mm: New
	* obj-c++.dg/attributes/proto-attribute-1.mm: New

From-SVN: r164700