For SIOCSIFADDR, don't call if_up() since it would attempt to add the

route to the destination twice.  Now that brian has fixed route.c to no
longer accept this second route, this long-standing nuisance became a
showstopper bug for sppp users.

In retrospect, this is the same fix as the one in rev 1.78 of if_sl.c;
most likely the original version of sppp has been cloned from SLIP. ;-)

sys/net/if_spppsubr.c

@@ -1024,7 +1024,8 @@ sppp_ioctl(struct ifnet *ifp, IOCTL_CMD_T cmd, void *data)
 		break;
 
 	case SIOCSIFADDR:
-		if_up(ifp);
+		/* set the interface "up" when assigning an IP address */
+		ifp->if_flags |= IFF_UP;
 		/* fall through... */
 
 	case SIOCSIFFLAGS: