Qt4 is dead and going away, please check if this can be run with PyQt5 instead. Support for it in matplotlib exists.
This is an optional runtime-only dependency. I'd just drop the USE flag completely.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=1e8f3957c0a197a0127c0c55f953f4e638053996 commit 1e8f3957c0a197a0127c0c55f953f4e638053996 Author: Andreas Sturmlechner <asturm@gentoo.org> AuthorDate: 2018-01-14 13:19:30 +0000 Commit: Andreas Sturmlechner <asturm@gentoo.org> CommitDate: 2018-01-14 13:21:29 +0000 sci-libs/scikits_image: Drop USE=qt4 Closes: https://bugs.gentoo.org/641938 Package-Manager: Portage-2.3.19, Repoman-2.3.6 sci-libs/scikits_image/scikits_image-0.13.0.ebuild | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)