and it proved quite easy in fact, with io::socket::ip which is a drop-in replacement for io::socket::inet... and thus, by changing 3 strings in audio-mpd, it is now ipv6 enabled - neat!
so, enable ipv6 on your software with the following one-liner:
easy, uh? who said ipv6 was difficult? :-)$ ack -l 'IO::Socket::INET' | xargs perl -pi -E 's/IO::Socket::INET/IO::Socket::IP/g'