diff -r 45d77f05d3a3 -r 8c0c3e9dd6a0 src/tile_map.cpp
--- a/src/tile_map.cpp	Fri Dec 21 08:34:53 2007 +0000
+++ b/src/tile_map.cpp	Fri Dec 21 19:21:21 2007 +0000
@@ -5,6 +5,7 @@
 #include "stdafx.h"
 #include "openttd.h"
 #include "tile_map.h"
+#include "core/math_func.hpp"
 
 Slope GetTileSlope(TileIndex tile, uint *h)
 {