(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.

src/lib/commands/set.c

@@ -63,7 +63,7 @@ set(void)
     struct trdstr trade;
     struct nstr_item ni;
     struct nstr_item ni_trade;
-    union trdgenstr item;
+    union empobj_storage item;
     struct sctstr sect;
     int freeslot;
     int foundslot;