(ITEM_MAX): New, value 9999.

(ITEM_MAX): New, value 9999.
(give, deliver_it): Use it instead of 9990.
(load_comm_ship, load_comm_land, rese): Use it instead of 9999.
(thre): Use it instead of 10000.
(check_market, explore, move, pln_dropoff): Use it instead of 32767.
(unload_it): Use it instead of 99999 (which couldn't possibly work,
but what do you expect from the autonav code).