(svn r22175) -Fix: [NewGRF] memory leak if a station newgrf contains prop 09 twice for the same station id

src/sprite.h

@@ -52,6 +52,8 @@ struct DrawTileSeqStruct {
 	}
 };
 
+const DrawTileSeqStruct *CopyDrawTileSeqStruct(const DrawTileSeqStruct *dtss);
+
 /** Ground palette sprite of a tile, together with its child sprites */
 struct DrawTileSprites {
 	PalSpriteID ground;           ///< Palette and sprite for the ground