Some platforms compile ncurses in such a way that the tinfo library needs to
be separately linked in (e.g. Gentoo).
The tinfo library is a low-level library being used by and bundled with
ncurses.
Adding '-ltinfo' to WINTTYLIB in the hint files was considered the most robust
solution to this problem. This still works on systems with ncurses 5.9.
Using pkg-config was ruled out as the default build of ncurses doesn't install
the necessary files.
This makes installing NetHack on a public server much easier.
Required some minor changes to the unix top-level Makefile, and
the other hints files; Makefile variable HACKDIR may not be a
full path anymore, use INSTDIR instead.
