You say you installed perl-5.20.x, Term::ReadKey, ..., and then show us libraries loading from ... /usr/lib/perl5/5.8.8/... Are you sure about this??

The TIOCGETP refers to an old, moldy, ancient, obsolete, tty controlling interface (sgtty) that was used on legacy bsd systems in ye olde times. That's been superseded by posix compatible tcgetattr/tcsetattr (termios). In other words, your system or your perl deployment is misconfigured, borkened, or simply rrong.