(svn r23459) -Fix: don't crash trying to draw airport tiles when the airport grf is missing

src/station_cmd.cpp

@@ -2613,8 +2613,9 @@ static void DrawTile_Station(TileInfo *ti)
 		total_offset = 0;
 	}
 
+	StationGfx gfx = GetStationGfx(ti->tile);
 	if (IsAirport(ti->tile)) {
-		StationGfx gfx = GetAirportGfx(ti->tile);
+		gfx = GetAirportGfx(ti->tile);
 		if (gfx >= NEW_AIRPORTTILE_OFFSET) {
 			const AirportTileSpec *ats = AirportTileSpec::Get(gfx);
 			if (ats->grf_prop.spritegroup[0] != NULL && DrawNewAirportTile(ti, Station::GetByTile(ti->tile), gfx, ats)) {
@@ -2654,7 +2655,7 @@ static void DrawTile_Station(TileInfo *ti)
 		palette = PALETTE_TO_GREY;
 	}
 
-	if (layout == NULL && (t == NULL || t->seq == NULL)) t = GetStationTileLayout(GetStationType(ti->tile), GetStationGfx(ti->tile));
+	if (layout == NULL && (t == NULL || t->seq == NULL)) t = GetStationTileLayout(GetStationType(ti->tile), gfx);
 
 	/* don't show foundation for docks */
 	if (ti->tileh != SLOPE_FLAT && !IsDock(ti->tile)) {