The Nvidia Cuda SDK does not contain any files used by libomp, the dependancy should be changed to Nvidia Cuda Toolkit. I have tested this on my machine, and it builds correctly. This is a oneline change in the ebuilds for libomp.
I really have no clue about CUDA nor any hardware to test it, so I'm going to trust you on this one.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=60277c194990f22a084d2e73f56f26a1fd32c41c commit 60277c194990f22a084d2e73f56f26a1fd32c41c Author: Michał Górny <mgorny@gentoo.org> AuthorDate: 2019-02-07 14:05:50 +0000 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: 2019-02-07 14:20:10 +0000 sys-libs/libomp: Fix cuda-dep to nvidia-cuda-toolkit Depend on dev-util/nvidia-cuda-toolkit rather than nvidia-cuda-sdk, as suggested by Robert. Closes: https://bugs.gentoo.org/677364 Signed-off-by: Michał Górny <mgorny@gentoo.org> sys-libs/libomp/{libomp-6.0.1.ebuild => libomp-6.0.1-r1.ebuild} | 2 +- sys-libs/libomp/{libomp-7.0.1.ebuild => libomp-7.0.1-r1.ebuild} | 2 +- sys-libs/libomp/libomp-7.0.9999.ebuild | 2 +- sys-libs/libomp/libomp-8.0.9999.ebuild | 2 +- sys-libs/libomp/libomp-9999.ebuild | 2 +- 5 files changed, 5 insertions(+), 5 deletions(-)