MFH: r422579

irc/irssi: Update to 0.8.20

• Add gettext-runtime to USES per poudriere's warning

https://irssi.org/security/irssi_sa_2016.txt

PR: 212888
Security: CVE-2016-7044
Security: CVE-2016-7045

Approved by: ports-secteam (with hat)