--- a/src/tunnel_map.cpp	Sat Jun 02 19:59:29 2007 +0000
+++ b/src/tunnel_map.cpp	Sat Jul 14 19:42:58 2007 +0000
@@ -39,7 +39,7 @@
  * @param dir  the direction to start searching to.
  * @return true if and only if there is a tunnel.
  */
-static bool IsTunnelInWayDir(TileIndex tile, uint z, DiagDirection dir)
+bool IsTunnelInWayDir(TileIndex tile, uint z, DiagDirection dir)
 {
 	TileIndexDiff delta = TileOffsByDiagDir(dir);
 	uint height;