the ebuild for bind-tools doesn't have idn support, so there is no way to get idn-aware versions of dig, host and nslookup the ebuild for bind has idn support, but removes the binaries for dig, host and nslookup before installing them (because they are provided by bind-tools)
fixed in 9.2.6-r1 and 9.3.2-r1. thanks, Christian.