simline/certificate_user_password_authentication test fails:

Testing unit: authentication with client certificate and username and password
	no client certificate: failed
		reason: Wrong return code: expected=Security problem, returned=Network problem (https://[::1]:47841/DS/dz: Failure when receiving data from the peer)
	wrong client certificate: failed
		reason: Wrong return code: expected=Security problem, returned=Network problem (https://[::1]:47841/certds/DS/dz: Failure when receiving data from the peer)
	invalid username: passed
	valid login: passed
	log into out-of-order server: passed
Test results: unit = authentication with client certificate and username and password, passed = 3, failed = 2

This is triggered by upgrading gnutls from 3.6.3-4 to 3.6.4-1. Log shows:

$ ./certificate_user_password_authentication
Testing unit: authentication with client certificate and username and password
Disabling server identity verification. That was your decision.
Connection accepted
TLS handshake failed: No certificate was found.
        no client certificate: failed
                reason: Wrong return code: expected=Security problem, returned=Network problem (https://[::1]:45363/DS/dz: Failure when receiving data from the peer)

This is probably the same issue as <https://gitlab.com/gnutls/gnutls/issues/615> (TLSv1.3 GnutTLS responding to a handshake from a client that does not expect post-handshake authentication results in return value == CURLE_RECV_ERROR in the client).