LibreOffice driver 2: MIT Kerberos vs Microsoft Kerberos

(See part 1 for general introduction)

LibreOffice currently - when it rebuilds libpq, such as for our
official MS Windows binaries - links libpq against only the MS
Windows built-in SSPI stuff, which if I understand well is an "embrace
and extend" Kerberos 5 implementation.

I wanted to understand the limitations (if any) of building libpq on
Windows only with the MS Windows-builtin Kerberos and not additionally
with MIT Kerberos.

The "gsslib" parameter in the connection string won't work, but will
that keep users from authenticating to some Kerberos domains, and/or
are there other (interoperability?) issues that make it strongly
desirable to link libpq with *both* SSPI *and* MIT krb5 (and its
gssapi_krb5 library)?

--
Lionel