(svn r3760) Replace some magic numbers for checking for a suitable slope for a level crossing by some less magic numbers. Quite similar to r3699, though this time for placing the rails
/* $Id$ */
static inline void MakeVoid(TileIndex t)
{
SetTileType(t, MP_VOID);
SetTileHeight(t, 0);
_m[t].m1 = 0;
_m[t].m2 = 0;
_m[t].m3 = 0;
_m[t].m4 = 0;
_m[t].m5 = 0;
_m[t].extra = 0;
}