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.
(launch_sat, scra, scut, scuttle_ship, scuttle_land, knockdown)
(ac_planedamage, detonate, attack_val, defense_val, air_damage)
(msl_intercept, msl_launch_mindam, pln_prewrite, shp_prewrite):
Simplify unit destruction: just zero efficiency, leave makelost()
etc. to the prewrite callback.
instead of declaring them all over the place. This uncovered type
errors:
(s_p_etu, adj_update): Defined long, sometimes declared int. Kills
big endian machines where sizeof(long) != sizeof(int). Change to
int.
(set_option, delete_option, optstrset, intset, floatset, doubleset,
longset, optionset, optiondel, worldxset): Change linkage to static.
