(svn r5315) -Fix: Prohibit altering a road tile while road works are in progress

This fixes some glitches like "turning" the excavation by adding/removing road bits or removing the road piece

lang/english.txt

@@ -1499,6 +1499,7 @@ STR_RAILROAD_TRACK_WITH_COMBOSIGNALS                            :Railway track w
 
 ##id 0x1800
 STR_1801_MUST_REMOVE_ROAD_FIRST                                 :{WHITE}Must remove road first
+STR_ROAD_WORKS_IN_PROGRESS                                      :{WHITE}Road works in progress
 STR_1802_ROAD_CONSTRUCTION                                      :{WHITE}Road Construction
 STR_1803_SELECT_ROAD_BRIDGE                                     :{WHITE}Select Road Bridge
 STR_1804_CAN_T_BUILD_ROAD_HERE                                  :{WHITE}Can't build road here...

lang/german.txt

@@ -1500,6 +1500,7 @@ STR_RAILROAD_TRACK_WITH_COMBOSIGNALS                            :Gleis mit kombi
 
 ##id 0x1800
 STR_1801_MUST_REMOVE_ROAD_FIRST                                 :{WHITE}Straße muss erst entfernt werden
+STR_ROAD_WORKS_IN_PROGRESS                                      :{WHITE}Straßenarbeiten sind im Gange
 STR_1802_ROAD_CONSTRUCTION                                      :{WHITE}Straßenbau
 STR_1803_SELECT_ROAD_BRIDGE                                     :{WHITE}Brücke wählen
 STR_1804_CAN_T_BUILD_ROAD_HERE                                  :{WHITE}Kann hier keine Straße bauen...

rail_cmd.c

@@ -286,12 +286,14 @@ int32 CmdBuildSingleRail(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 
 			if (!EnsureNoVehicle(tile)) return CMD_ERROR;
 
-			if (GetRoadTileType(tile) == ROAD_TILE_NORMAL && (
-						(track == TRACK_X && GetRoadBits(tile) == ROAD_Y) ||
-						(track == TRACK_Y && GetRoadBits(tile) == ROAD_X)
-					)) {
-				if (flags & DC_EXEC) {
-					MakeRoadCrossing(tile, GetTileOwner(tile), _current_player, (track == TRACK_X ? AXIS_Y : AXIS_X), p1, GetTownIndex(tile));
+			if (GetRoadTileType(tile) == ROAD_TILE_NORMAL) {
+				if (HasRoadWorks(tile)) return_cmd_error(STR_ROAD_WORKS_IN_PROGRESS);
+
+				if ((track == TRACK_X && GetRoadBits(tile) == ROAD_Y) ||
+						(track == TRACK_Y && GetRoadBits(tile) == ROAD_X)) {
+					if (flags & DC_EXEC) {
+						MakeRoadCrossing(tile, GetTileOwner(tile), _current_player, (track == TRACK_X ? AXIS_Y : AXIS_X), p1, GetTownIndex(tile));
+					}
 				}
 				break;
 			}

road_cmd.c

@@ -155,6 +155,8 @@ int32 CmdRemoveRoad(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 					RoadBits present = GetRoadBits(tile);
 					RoadBits c = pieces;
 
+					if (HasRoadWorks(tile)) return_cmd_error(STR_ROAD_WORKS_IN_PROGRESS);
+
 					if (GetTileSlope(tile, NULL) != SLOPE_FLAT &&
 							(present == ROAD_Y || present == ROAD_X)) {
 						c |= (c & 0xC) >> 2;
@@ -291,6 +293,8 @@ int32 CmdBuildRoad(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 		case MP_STREET:
 			switch (GetRoadTileType(tile)) {
 				case ROAD_TILE_NORMAL:
+					if (HasRoadWorks(tile)) return_cmd_error(STR_ROAD_WORKS_IN_PROGRESS);
+
 					existing = GetRoadBits(tile);
 					if ((existing & pieces) == pieces) {
 						return_cmd_error(STR_1007_ALREADY_BUILT);

tunnelbridge_cmd.c

@@ -343,8 +343,9 @@ int32 CmdBuildBridge(TileIndex end_tile, uint32 flags, uint32 p1, uint32 p2)
 				break;
 
 			case MP_STREET:
-				if (GetRoadTileType(tile) != ROAD_TILE_NORMAL ||
-						GetRoadBits(tile) != (direction == AXIS_X ? ROAD_Y : ROAD_X)) {
+				if (GetRoadTileType(tile) != ROAD_TILE_NORMAL) goto not_valid_below;
+				if (HasRoadWorks(tile)) return_cmd_error(STR_ROAD_WORKS_IN_PROGRESS);
+				if (GetRoadBits(tile) != (direction == AXIS_X ? ROAD_Y : ROAD_X)) {
 					goto not_valid_below;
 				}
 				transport_under = TRANSPORT_ROAD;