(svn r22702) [1.1] -Backport from trunk:

- Fix: Cost of adding an extra road type to a bridge or tunnel was undercalculated [FS#4680, FS#4681] (r22700, r22699)
- Fix: Only insert cleared object tiles into _cleared_object_areas if clearing actually succeeds, else subsequential tests of the same tile will be skipped and considered successful [FS#4694] (r22698)
- Fix: When building a house it could be built at the wrong place if multitile houses failed some tests (r22697)

src/town_cmd.cpp

@@ -2125,8 +2125,16 @@ static bool BuildTownHouse(Town *t, TileIndex tile)
 	}
 
 	uint maxz = GetTileMaxZ(tile);
+	TileIndex baseTile = tile;
 
 	while (probability_max > 0) {
+		/* Building a multitile building can change the location of tile.
+		 * The building would still be built partially on that tile, but
+		 * its nothern tile would be elsewere. However, if the callback
+		 * fails we would be basing further work from the changed tile.
+		 * So a next 1x1 tile building could be built on the wrong tile. */
+		tile = baseTile;
+
 		uint r = RandomRange(probability_max);
 		uint i;
 		for (i = 0; i < num; i++) {