diff --git a/src/functions.h b/src/functions.h
--- a/src/functions.h
+++ b/src/functions.h
@@ -26,7 +26,7 @@ void TileLoopClearHelper(TileIndex tile)
 bool CheckCompanyHasMoney(CommandCost cost);
 void SubtractMoneyFromCompany(CommandCost cost);
 void SubtractMoneyFromCompanyFract(CompanyID company, CommandCost cost);
-bool CheckOwnership(Owner owner);
+bool CheckOwnership(Owner owner, TileIndex tile = 0);
 bool CheckTileOwnership(TileIndex tile);
 
 /* misc functions */