Packages with the protobuf use flag

net-dns / pdns : The PowerDNS Daemon

Enable support for dev-libs/protobuf.

net-dns / pdns-recursor : The PowerDNS Recursor

Enable support for dev-libs/protobuf.

net-misc / quagga : A free routing daemon replacing Zebra supporting RIP, OSPF and BGP

Enable support for dev-libs/protobuf