obsq_sortcmp
solv_sort(ti->elements, ti->count / 2, 2 * sizeof(Id), obsq_sortcmp, pool);
if (obsq_sortcmp(q, q + 2, pool) < 0)
solv_sort(pkgs->elements, pkgs->count / 2, 2 * sizeof(Id), obsq_sortcmp, pool);