anchor.diff:  	if(!overlays)
   		return
   	overlays = build_appearance_list(overlays)
  -	LAZYINITLIST(add_overlays) //always initialized after this point
  +	LAZYINITLIST(add_overlays)
   	LAZYINITLIST(remove_overlays)
   	var/a_len = add_overlays.len
   	var/r_len = remove_overlays.len
  
positive.code: 				continue
  			STAT_START_STOPWATCH
  			COMPILE_OVERLAYS(A)
  			STAT_STOP_STOPWATCH
  			STAT_LOG_ENTRY(stats, A.type)
  		if(mc_check)
  
negative.code: 	//If not already queued and there is work to be done
  	if(NOT_QUEUED_ALREADY && (fa_len != a_len || fr_len != r_len ))
  		QUEUE_FOR_COMPILE
  	UNSETEMPTY(add_overlays)
  
  /atom/proc/add_overlay(list/overlays)
  	if(!overlays)
  