Do something reasonable when IPV6_JOIN_GROUP fails.
Do something reasonable when IPV6_JOIN_GROUP fails.

Gwendocg/babeldToS,wlanslovenija/babeld,Gwendocg/babeldToS,tcatm/babeld,sudomesh/babeld,woniullb/babeld,wlanslovenija/babeld,Drooids/babeld,jech/babeld,boutier/babeld,dtaht/babeld-shortrtt-metrics,jech/babeld