NUK_BLD_WORK): New, to encapsulate the formula in one place.
(SCT_MINEFF): New. Use it instead of literal 20.
(buil): Use CANT_HAPPEN() for internal error.
(build_ship, build_land, build_bridge, build_nuke, build_plane,
build_tower): Simplify avail calculation.
(lupgr, supgr, pupgr): Charge 15% of total build avail instead of an
undocumented amount computed from build lcm and hcm.
(build_ship, build_land, build_bridge, build_nuke, build_plane,
build_tower, lupgr, supgr, pupgr): Fix reporting of required avail
when there's not enough. Closes#942823.
(lupgr, supgr, pupgr): Code printed cost rounded down, but required
and charged unrounded cost. Confusing. Round cost down, like the
build command. Closes#942811.
(UPGR_COST, UPGR_EFF, lupgr, supgr, pupgr): New UPGR_COST, UPGR_COST replace
literal values.
(show_bridge, show_tower): Don't claim bridge building requires
`workers' (whatever that is), since it doesn't.
(genitem_ca, ship_ca, plane_ca, land_ca): Remove selector "sell".
(comstr, trdstr): Members trd_price, com_price have no effect. Use
them instead of trd_maxprice, com_maxprice and remove the latter.
(commodity_ca, trade_ca): Remove selector "maxprice".
between headers. Code is now fully prototyped and compiles cleanly
with gcc -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs
-Wredundant-decls. Closes#723788.
thread entrypoints:
(lwpSelect, shutdown_sequence): Parameters didn't match thread entry
point prototype.
(lwpEntryPoint): Arguments didn't match thread entry point prototype.
Change linkage of functions without prototype declaration to static
where possible.
Remove some superflous declarations, replace others by suitable
includes.
