(nxtitemp, trade_getitem, trade_desc, trade_check_item_ok, nxtitem,

oprange, show_mission, nameofitem, build_mission_list_type,
unit_map, xdvisible, trdswitchown, ontradingblock, trad, check_trade,
unit_type_name, start_stop_unit, scut, scra, mission, multifire,
perform_mission, fuel, NSC_GENITEM): Replace struct genitem with
struct empobj.  Remove genitem.h and create a new file empobj.h.
Replace multiple instances of unions of ef_type structures with
one standard union empobj_storage which is a superset of the individual
instances.

include/lost.h

@@ -35,10 +35,10 @@
 #define LOST_H
 
 struct loststr {
-    /* initial part must match struct genitem */
+    /* initial part must match struct empobj */
     short ef_type;
     natid lost_owner;		/* Who lost it */
-    /* end of part matching struct genitem */
+    /* end of part matching struct empobj */
     int lost_uid;		/* lost ID (assigned, otherwise unused) */
     char lost_type;		/* Type of thing (ship, plane, nuke, land, sector) */
     short lost_id;		/* ID of lost thing */