Update ppg_subselect.c

to Support this SQL:
select
                c_count,
                count(*) as custdist
        from
                (
                        select
                                c_custkey,
                                count(o_orderkey)
                        from
                                customer left outer join orders on
                                        c_custkey = o_custkey
                                        and o_comment not like '%pending%accounts%'
                        group by
                                c_custkey
                ) as c_orders (c_custkey, c_count)
        group by
                c_count
        order by
                custdist desc,
                c_count desc
        LIMIT 1;