The old code used getstarg() to get an argument with a different
prompt than snxtitem() uses, then passed the value to snxtitem()
unchecked. If the player aborts, getstarg() returns a null pointer,
and snxtitem() prompts again. Affected:
* load/lload plane/land third argument; load_plane_ship(),
load_land_ship(), load_plane_land(), load_land_land()
* bomb, drop, fly, paradrop, recon and sweep second argument;
get_planes()
* tend and ltend second and fourth argument; ltend(), tend(),
tend_land()
* mission second argument; mission()
Fix by making snxtitem() taking a prompt argument, null pointer
requests the old prompt.
Use that to simplify multifire() and torp(). Change the other callers
to pass NULL.
other. Ensure headers in include/ can be included in any order
(except for econfig-spec.h, which is special). New header types.h to
help avoid inclusion cycles. Sort include directives. Remove some
superflous includes.
land units and nukes for selection type NS_LIST. Thus, unowned items
explicitly selected by item number are skipped, while the same items
selected implicitely by group, area or whatever are not. This makes
no sense. Some callers break the nstr_item abstraction to prevent the
skipping, so they get all items regardless of how they were selected.
All other callers filter out unowned items. This skipping misfeature
dates back to the very oldest known versions of Empire. Remove it.
Also remove skipping prevention hacks from callers.
(tend_nxtitem): Now identical to nxtitem(), except it lacks some extra
normalization of item coordinates, which should have no effect.
Replace by nxtitem().
