void *optval;
const void *optval;
setsockopt (fd, level, optname, optval, optlen)     int fd;     int level;     int optname;     void *optval;     size_t optlen;{  error_t err = HURD_DPORT_USE (fd, __socket_setopt (port,						     level, optname,						     optval, optlen));  if (err)    return __hurd_dfail (fd, err);  return 0;}