25 extern const byte _signal_along_trackdir[
TRACKDIR_END] = {
 
   26   0x8, 0x8, 0x8, 0x2, 0x4, 0x1, 0, 0,
 
   27   0x4, 0x4, 0x4, 0x1, 0x8, 0x2
 
   32 extern const byte _signal_against_trackdir[
TRACKDIR_END] = {
 
   33   0x4, 0x4, 0x4, 0x1, 0x8, 0x2, 0, 0,
 
   34   0x8, 0x8, 0x8, 0x2, 0x4, 0x1
 
   39 extern const byte _signal_on_track[] = {
 
   40   0xC, 0xC, 0xC, 0x3, 0xC, 0x3
 
   46 extern const TrackdirBits _exitdir_reaches_trackdirs[] = {
 
   69 extern const TrackBits _track_crosses_tracks[] = {
 
  112 extern const Trackdir _dir_to_diag_trackdir[] = {
 
  116 extern const TrackBits _corner_to_trackbits[] = {
 
  232     if (rti->
label == 0) 
continue;
 
  242     if ((rts & required) != required) 
continue;
 
  290     if (rti->
label == label) 
return r;
 
  293   if (allow_alternate_labels) {