void(* xt_sort_int)(int *a, size_t n)
void(* xt_sort_idxpos)(idxpos_type *v, size_t n)
void xt_quicksort_int(int *a, size_t n)
void xt_quicksort_index(Xt_int *v_idx, int n, int *v_pos, int reset_pos)
void xt_quicksort_idxpos(idxpos_type *v, size_t n)
void(* xt_sort_index)(Xt_int *a, int n, int *idx, int reset_index)