WIP | For Testing | Cross realm S4U2Self

[github at samba.org]

New comment by abartlet on Samba Github repository

https://github.com/samba-team/samba/pull/204#issuecomment-422655697
Comment:
Any chance you can rebase this work on https://gitlab.com/catalyst-samba/samba/commits/import-lorikeet-heimdal-201809182344-fast-nofail and https://gitlab.com/samba-team/devel/lorikeet-heimdal/tree/lorikeet-heimdal-201809182344-fast

or rebase my heimdal branch on this (I don't mind which).

I'm trying to import heimdal and this may help if you have sorted out some of the cross-realm stuff