Hi, I came by the same FTBFS and wanted to let you know that we picked upstream [1] to fix it. Hope that helps to get it resolved for you as well!
[1]: https://github.com/OpenSC/pam_p11/commit/55b3888d5e9208948a40725350ca2f50020c4838 -- Christian Ehrhardt Software Engineer, Ubuntu Server Canonical Ltd
