app-editors/nvi is based on very old code needing a lot of patches, and can be well replaced by >=app-edtors/vim-8.1.1155[minimal].
https://sites.google.com/a/bostic.com/keithbostic/files no patches and updates since 2010? Seems to be really dead. I think you should really last rite it. see "Removing a package" https://devmanual.gentoo.org/ebuild-maintenance/maintenance-tasks/ Please ask on IRC, if you need help.
It is not that dead, a few patches have been accepted since 2010: https://repo.or.cz/nvi.git The last time I heard anything from the maintainer was in January 2017.
The bug has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=fcf6743746ba9d9e498030239f53461da5145bc5 commit fcf6743746ba9d9e498030239f53461da5145bc5 Author: Michał Górny <mgorny@gentoo.org> AuthorDate: 2020-02-17 07:41:29 +0000 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: 2020-02-17 08:17:23 +0000 package.mask: Last rite app-editors/nvi Bug: https://bugs.gentoo.org/690102 Signed-off-by: Michał Górny <mgorny@gentoo.org> profiles/package.mask | 8 ++++++++ 1 file changed, 8 insertions(+)