Convert diagnostics to use quoting flag q 2/n
        * class.c (build_base_path, add_method, alter_access,
        handle_using_decl, check_bases,
        maybe_warn_about_overly_private_class, find_final_overrider,
        warn_hidden, finish_struct_anon,
        add_implicitly_declared_members,
        check_bitfield_decl, check_field_decls, layout_empty_base,
        build_base_field, check_methods, layout_virtual_bases,
        warn_about_ambiguous_bases, layout_class_type,
        finish_struct_1,
        resolve_address_of_overloaded_function, instantiate_type,
        note_name_declared_in_class): Use format flag "q" for quoting.

From-SVN: r88473