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.
EMPPATH() to use EMPDIR. This avoids triggering MSVC bugs, and drops
support for traditional, pre-ISO cpp. Closes#753935.
(gamedir, lostfil, playerbin, updatebin): Unused, remove.