We're working on fixing things so that git.postgresql.org will advertise a cert chain that is compatible with older OpenSSL versions. I thought that was supposed to happen this weekend, but evidently it hasn't yet. You will need an up-to-date (less than several years old) /etc/ssl/certs.pem, but no software mods should be needed. I'd counsel just waiting a day or two more before trying to resurrect curculio.
It was indeed supposed to, but didn't. It has now been done though, so git.postgresql.org should now be compatible with ancient OpenSSL.