double start = DBL_MAX, end = DBL_MIN;
Track *first_track=0, *last_track = 0;
for( Track *track=tracks->first; track; track=track->next ) {
double start = DBL_MAX, end = DBL_MIN;
Track *first_track=0, *last_track = 0;
for( Track *track=tracks->first; track; track=track->next ) {