Summary says it all. The ebuild would have to --enable-asciidoc with USE=nls. (When doing so, the next problem is that LINGUAS is ignored.) Not sure if depending on Ruby is an option for a system package like this. If not, then maybe the ebuild should --disable-poman unconditionally.
Created attachment 865306 [details] build.log
Created attachment 865307 [details] emerge --info