Add ability to compile out the debugging code.
Add ability to compile out the debugging code.

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