Created attachment 319876 [details]
Please add the attached ebuild. It's a dependency of dev-tex/biber (bug #340353).
XML::Writer::String is not used by biblatex-biber-1.2.
Could you elaborate? Just downloaded biblatex.biber 1.2, and its Build.PL checks for XML::Writer::String. However, I was unable to find any reference to XML::Writer::String in biber's source. So is biber's Build.PL lying?
Reported upstream. See https://sourceforge.net/tracker/?func=detail&aid=3566721&group_id=228270&atid=1073792 for further details.