The claws-mail-notification plugin includes libnotify support so the libnotify use flag should be added to the ebuild along with the dependency. See the attached diff for possible changes to the latest version's ebuild.
Created attachment 135942 [details] claws-mail-notification-libnotify.diff add libnotify support
Comment on attachment 135942 [details] claws-mail-notification-libnotify.diff This is not a valid usage of USE flags; the flag doesn't do anything useful. http://www.gentoo.org/proj/en/qa/automagic.xml http://devmanual.gentoo.org/general-concepts/use-flags/index.html
Created attachment 135943 [details, diff] claws-mail-notification-0.12.1.ebuild.diff
Thanks for the links to the automagic docs. It did feel like the ebuild was missing something else.
Added tot 0.14, fresh in the tree with claws-mail 3.2.0. Thanks for the suggestion!