PR c++/21581

        * parser.c (cp_parser_declaration): Support attributes on
        anonymous namespaces.
        * name-lookup.c (push_namespace_with_attribs): Anonymous
        namespaces default to hidden visibility.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@112250 138bc75d-0d04-0410-961f-82ee72b054a4