GSSAPI auth missing?

I was about to configure kerberos connections to my test OpenLDAP system (2.4.7, debian sid packages) when I discovered an oddity....

# ldapsearch -x -b "" -s base -LLL supportedSASLMechanisms dn: supportedSASLMechanisms: CRAM-MD5 supportedSASLMechanisms: DIGEST-MD5 supportedSASLMechanisms: LOGIN supportedSASLMechanisms: PLAIN supportedSASLMechanisms: NTLM

I don't see GSSAPI in the list. My searching of the doc and google has met with no real results. What must I do to get GSSAPI added as a supported mechanism?

Pat