It compiles just fine with USE=-doc and without dev-util/gtk-doc.
Created attachment 319414 [details, diff] Patch for the ebuild
+ 13 Jan 2013; Justin Lecher <jlec@gentoo.org> -dee-1.0.10.ebuild, + -dee-1.0.12.ebuild, dee-1.0.14.ebuild, metadata.xml: + Drop old; only depend on dev-util/gtk-doc with USE=doc, #428318; reduce test + to basic set as advanced are broken on several places, #450196 and + https://bugs.launchpad.net/dee +