CONF_ENABLE_IPV6
(sp->confflags & CONF_ENABLE_IPV6)))
spr->defs.enable_ipv6 = (sp->confflags & CONF_ENABLE_IPV6) != 0;
sp->confflags |= CONF_ENABLE_IPV6;
sp->confflags &= ~CONF_ENABLE_IPV6;
!(sp->confflags & CONF_ENABLE_IPV6))
sp->confflags |= CONF_ENABLE_IPV6;