irc/epic4: Remove obsolete TERMCAP option, link with libncurses alway

The TERMCAP option avoided linking with libcurses (which is symlinked to
libncurses) in order to link with libtermcap (which is also symlinked to
libncurses).

Remove the TERMCAP option completely and link directly to libncurses in
any case.

PR: 206947
approved by: jpaetzel@ (maintainer)