gnutls-cli cannot specify server name while doing xmpp starttls

Description of the feature:

XMPP starttls sends the servername before requesting STARTTLS. However, the server might reject that request if the XMPP domains does not match (/host-unknown). This happens specially when "IN SRV" entries are in use for XMPP.

Applications that this feature may be relevant to:

gnutls-cli --verify-hostname=mydomain.com --starttls-proto=xmpp jabber.mydomain.com:xmpp-client

--verify-hostname or --sni-hostname does not help. It does work if mydomain.com IN A matches jabber.mydomain.com. However, this should not be a requirement.

Is this feature implemented in other libraries (and which)

openssl s_client -starttls xmpp -xmpphost mydomain.com -connect jabber.mydomain.com:xmpp-client