[krbdev.mit.edu #8625] Caching Forwarded TGTs

[Todd Lubin via RT]

When requesting a forwarded TGT, a client always talks to the KDC.
[krb5_fwd_tgt_creds]
always calls [krb5_get_cred_via_tkt].

When ssh is using GSSAPIDelegateCredentials=yes, this generates KDC traffic
on every new ssh connection.

You could imagine caching forwarded TGTs to avoid this. If addresses are
used, you could cache a forwarded TGT for each destination host.

Is there a particular reason that this is not done? If no, I can submit a
patch for this.