Feature #6610: Allow towns to build houses on road turns (#6758)

src/map_func.h

@@ -362,6 +362,18 @@ static inline TileIndexDiff TileOffsByDir(Direction dir)
 	return ToTileIndexDiff(_tileoffs_by_dir[dir]);
 }
 
+/**
+ * Adds a Direction to a tile.
+ *
+ * @param tile The current tile
+ * @param dir The direction in which we want to step
+ * @return the moved tile
+ */
+static inline TileIndex TileAddByDir(TileIndex tile, Direction dir)
+{
+	return TILE_ADD(tile, TileOffsByDir(dir));
+}
+
 /**
  * Adds a DiagDir to a tile.
  *