IFACE_SYSTEM
if (!iface->addr[n].system && (how & IFACE_SYSTEM))
newaddr.system = !!(how & IFACE_SYSTEM);
IFACE_ADD_FIRST|IFACE_FORCE_ADD|IFACE_SYSTEM))
IFACE_CLEAR_ALIASES|IFACE_SYSTEM);
IFACE_ADD_FIRST|IFACE_FORCE_ADD|IFACE_SYSTEM))
IFACE_CLEAR_ALIASES|IFACE_SYSTEM);