Enable UPnP port mapping support

Packages describing “upnp” as local USE flag

Package “upnp” Flag Description
media-video/vlc Enable support for the Intel SDK stack based UPnP discovery module instead of CyberLink
net-im/gajim Ability to request your router to forward port for file transfer
net-p2p/bitcoind Enable Universal Plug and Play
net-p2p/ktorrent Forward ports using UPnP
net-p2p/bitcoin-qt Enable Universal Plug and Play

All packages providing a “upnp” USE flag (22)