Add support for IP version 6

Packages describing “ipv6” as local USE flag

Package“ipv6” Flag Description
app-backup/baculaSupport IPV6 protocol"
dev-lang/phpSupport IPv6 connectivity in fopen and friends, and v6 address conversions in functions like inet_pton and inet_ntop.
net-analyzer/muninAdd support for IPv6 in munin-node. IPv6 support for the master is always enabled, but the node requires a newer version of dev-perl/Net-Server, capable of listening to IPv6 sockets.
net-analyzer/nagios-pluginsEnable ipv6 checks.
net-analyzer/zabbixTurn on support of IPv6
net-dns/rbldnsdSupport listening on ipv6 addresses and ipv6 database entries.
net-firewall/shorewallAdds the capability to create a full IPv6 firewall (requires net-firewall/shorewall ipv4 USE flag)
net-firewall/ufwIPv6 support for iptables
net-libs/miniupnpcRun tests requiring IPv6-enabled kernel.
sys-cluster/glusterfsUse IPv6 by default, requires libtirpc

All packages providing a “ipv6” USE flag (122)