I have just realized there is a newer minor release of unbound available since past January. Compilation works with previous ebuild, and it runs.
The bug has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=49bebd6e698b163d524aa4cc52f82c000140545c commit 49bebd6e698b163d524aa4cc52f82c000140545c Author: Sam James <sam@gentoo.org> AuthorDate: 2023-06-19 22:06:05 +0000 Commit: Sam James <sam@gentoo.org> CommitDate: 2023-06-19 22:06:21 +0000 net-dns/unbound: add 1.17.1 Bug: https://bugs.gentoo.org/908439 Signed-off-by: Sam James <sam@gentoo.org> net-dns/unbound/Manifest | 2 + net-dns/unbound/unbound-1.17.1.ebuild | 212 ++++++++++++++++++++++++++++++++++ 2 files changed, 214 insertions(+)