I filed a report with the LibreSSL folks, and the answer was basically "yeah, we know RSA-PSS doesn't work; there are multiple things that need fixing" [1]. So it seems like we'd better find a way to skip that test case when using LibreSSL. Not sure what the most appropriate check would look like.
regards, tom lane
[1] https://marc.info/?l=libressl&m=174664225002441&w=2
