sci-electronics/qucs 0.0.18 version is available from 31/08/2014 http://sourceforge.net/projects/qucs/files/qucs/ In portage the only version available is 0.0.17.130503 Please add new version to portage
This seems to be a fairly simple bump, just copy the ebuild with the new name - qucs-0.0.18.ebuild
When copying and renaming the qucs ebuild into a local overlay, the configure step complains it requires bison 2.6.0. Current stable is 2.4.3 and the 2.6 branch is not in the tree. I upgraded to sys-devel/bison-2.7.1 (~amd64). Then qucs emerged fine.
commit fb84c5b03a3b0eb15c881152a2b447f6b25179fa Author: Michał Górny <mgorny@gentoo.org> AuthorDate: Fri Jul 1 16:20:21 2016 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: Fri Jul 1 16:27:32 2016 sci-electronics/qucs: Bump to 0.0.18