list_coll_offset
return (list_coll_offset(ss1, ss2, 0));
return (list_coll_offset(ss1, ss2, N)); \
int list_coll_offset(struct sort_list_item **ss1, struct sort_list_item **ss2, size_t offset);
if (list_coll_offset(&(sl->tosort[0]), &(sl->tosort[1]),