Place built libraries for Lua and pdcurses into lib instead of the
more transient src/o subfolder.
Remove a kludge involving sys/windows/stub-pdcscrn.c.
Don't link pdcurses into NetHackW.exe (required a couple of stubs
since NetHack.exe and NetHackW.exe currently share object files
under the visual studio nmake build.
(Note: This may require a couple of follow-on minor modifications
to the mingw build. If so, the CI will flag that for us after this
commit)
fa4ad397dc