Set LIB_PACKAGE= in lib/ncurses/Makefile.inc so the ncurses libraries
go into the ncurses-lib subpackage rather than the base package. This
means applications that depend on ncurses can be installed without
needing to install the various utilities and manpages.
This removes a dependency from runtime to ncurses (it now depends on
ncurses-lib instead).
MFC after: 3 days