Created attachment 437238 [details] emerge --info Hello ${SUBJECT}. Please fix.
Created attachment 437240 [details] build.log
uhm...libxfce4ui is being transitioned to gtk3 as all of xfce4 is being upgraded to gtk3 for the next release this is "development release for testing" gtk3 probably should not be optional for this version of the ebuild but required ..
commit 8567acfc4bd3cd60ebf2b247734e1fb0e7e4cb35 Author: Michał Górny <mgorny@gentoo.org> AuthorDate: Thu Jun 23 16:34:40 2016 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: Thu Jun 23 17:06:26 2016 xfce-base/libxfce4ui: Force GTK+3 to work-around build failure, #585684 I can revisit this if upstream decides to continue support for GTK+2-only builds. So far doesn't look like it's expected to work.