Merge branch 'master' into jgrpp

# Conflicts:
#	src/landscape.cpp
#	src/landscape.h
#	src/misc_gui.cpp
#	src/newgrf_commons.cpp
#	src/order_cmd.cpp
#	src/pathfinder/yapf/yapf_base.hpp
#	src/station_cmd.cpp
#	src/tunnelbridge_cmd.cpp
#	src/vehicle.cpp
#	src/water_cmd.cpp
#	src/window.cpp

src/town_cmd.cpp

@@ -1151,7 +1151,7 @@ static bool IsRoadAllowedHere(Town *t, TileIndex tile, DiagDirection dir)
 		}
 	}
 
-	Slope cur_slope = _settings_game.construction.build_on_slopes ? GetFoundationSlope(tile) : GetTileSlope(tile);
+	Slope cur_slope = _settings_game.construction.build_on_slopes ? std::get<0>(GetFoundationSlope(tile)) : GetTileSlope(tile);
 	bool ret = !IsNeighborRoadTile(tile, dir, t->layout == TL_ORIGINAL ? 1 : 2);
 	if (cur_slope == SLOPE_FLAT) return ret;
 
@@ -1697,7 +1697,7 @@ static void GrowTownInTile(TileIndex *tile_ptr, RoadBits cur_rb, DiagDirection t
 			auto get_road_slope = [rcmd](TileIndex t) -> Slope {
 				Slope slope = GetTileSlope(t);
 				extern Foundation GetRoadFoundation(Slope tileh, RoadBits bits);
-				ApplyFoundationToSlope(GetRoadFoundation(slope, rcmd), &slope);
+				ApplyFoundationToSlope(GetRoadFoundation(slope, rcmd), slope);
 				return slope;
 			};