Add forgotten prototype.
Add forgotten prototype.

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