(svn r11760) -Codechange: unify the way how other end of a tunnel/bridge is determined at some places

-Fix: adding road/tram to tram/road bridge was cheaper by one tile

src/tunnelbridge_map.h

@@ -8,6 +8,8 @@
 #include "direction_func.h"
 #include "core/bitmath_func.hpp"
 #include "tile_map.h"
+#include "bridge_map.h"
+#include "tunnel_map.h"
 
 
 /**
@@ -63,4 +65,16 @@ static inline void SetTunnelBridgeSnowOrDesert(TileIndex t, bool snow_or_desert)
 	SB(_m[t].m4, 7, 1, snow_or_desert);
 }
 
+/**
+ * Determines type of the wormhole and returns its other end
+ * @param t one end
+ * @pre IsTileType(t, MP_TUNNELBRIDGE)
+ * @return other end
+ */
+static inline TileIndex GetOtherTunnelBridgeEnd(TileIndex t)
+{
+	assert(IsTileType(t, MP_TUNNELBRIDGE));
+	return IsTunnel(t) ? GetOtherTunnelEnd(t) : GetOtherBridgeEnd(t);
+}
+
 #endif /* TUNNELBRIDGE_MAP_H */