After system was upgraded to libconfig-1.7.3, sslh suddenly stopped working with > At least one target protocol must be specified. See $URL for more details.
Ah, so libconfig say it shouldn't have been used, but obviously folks were relying on it (see https://github.com/hyperrealm/libconfig/issues/196#issuecomment-866299567). Patch for sslh: https://github.com/yrutschle/sslh/commit/24e7f46a431b59043bf534eb7cdab76c4ffd595a
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=8361d101844ec8f2587f43590d7ca7c569e728e3 commit 8361d101844ec8f2587f43590d7ca7c569e728e3 Author: Craig Andrews <candrews@gentoo.org> AuthorDate: 2021-08-16 03:39:37 +0000 Commit: Craig Andrews <candrews@gentoo.org> CommitDate: 2021-08-16 03:40:42 +0000 net-misc/sslh: libconfig 1.7.3 compatibility Closes: https://bugs.gentoo.org/808525 Package-Manager: Portage-3.0.20, Repoman-3.0.3 Signed-off-by: Craig Andrews <candrews@gentoo.org> .../sslh/files/sslh-1.21c-libconfig-1.7.3.patch | 92 ++++++++++++++++++++++ net-misc/sslh/sslh-1.21c-r3.ebuild | 77 ++++++++++++++++++ 2 files changed, 169 insertions(+)