(svn r20559) -Fix [FS#4045]: make sure that all vehicles are build in the most northern depot/hangar tile

src/water_map.h

@@ -197,6 +197,19 @@ static inline DiagDirection GetShipDepotDirection(TileIndex t)
 	return XYNSToDiagDir(GetShipDepotAxis(t), GB(_m[t].m5, 0, 1));
 }
 
+/**
+ * Get the most northern tile of a ship depot.
+ * @param tile One of the tiles of the ship depot.
+ * @return The northern tile of the depot.
+ */
+static TileIndex GetShipDepotNorthTile(TileIndex t)
+{
+	assert(IsShipDepot(t));
+	TileIndex tile2 = GetOtherShipDepotTile(t);
+
+	return t < tile2 ? t : tile2;
+}
+
 /**
  * Is it a water lock tile?
  * @param t Water tile to query.