Seems one of the only dependencies or uses of app-crypt/dirmngr in the Gentoo tree is kde-base/kgpg's if ! has_version app-crypt/dirmngr ; then elog "For improved key search functionality, install app-crypt/dirmngr." fi This is of course a trivial matter, but as a heads up please note that as of GnuPG 2.1 the dirmngr will no longer be shipped as an own package but be an embedded part of GnuPG. There doesn't seem to be sufficient use of this package in the tree to require a virtual for it, but one alternative might be to check for ${EPREFIX}/usr/bin/dirmngr directly.
If it is included in gnupg 2.1, we probably just need to check for ! dirmngr and !>gnupg-2.1, because kgpg depends on gnupg anyway.
Thanks for reporting. This is fixed in cvs and git now. + + 21 Jun 2015; Johannes Huber <johu@gentoo.org> +kgpg-4.14.3-r1.ebuild: + Adjust postinst check for app-crypt/gnupg-2.1, bug #535834. + https://gitweb.gentoo.org/proj/kde.git/commit/?id=88d7b7354283dee281c7496d33cefec53701c300