The kgssapi used detailed internal knowledge of
the Heimdal (up to vers 1.5) kerberos context.
This would not work for MIT Kerberos.
D51731 patches the kgssapi so that it acquires
the information needed to establish a RPCSEC_GSS
context via new upcalls to the gssd daemon.
This avoids needing internal knowledge of MIT's
Kerberos, by using the gss_krb5_export_lucid_sec_context()
library function to acquire the needed information.
This patch adds these upcalls.
I left the old upcalls intact, although they should
be removed once the old Heimdal 1.5 code is
removed from /usr/src.