Implement final/override for member functions.

Implement final/override for member functions.

gcc/
	* tree.h (TYPE_UNQUALIFIED, TYPE_QUAL_CONST): Convert to enum.
	(TYPE_QUAL_VOLATILE, TYPE_QUAL_RESTRICT): Likewise.
gcc/cp/
	* class.c (check_for_override): Check for DECL_OVERRIDE_P.
	* cp-tree.h (DECL_OVERRIDE_P, DECL_FINAL_P): New.
	(cp_virt_specifiers, enum virt_specifier): New.
	* decl.c (set_virt_specifiers): New.
	(grokdeclarator): Use them. Diagnose virt-specifiers on non-fields.
	* parser.c (make_call_declarator): add virt-specifiers parameter.
	(cp_parser_lambda_declarator_opt): Adjust.
	(cp_parser_direct_declarator): Likewise.
	(cp_parser_virt_specifier_seq_opt): New.
	* search.c (check_final_overrider): Diagnose attempts to override
	a final member function.

From-SVN: r173581