repeat performance by introducing a script that runs configure with and
without Kerberos, diffs the result and generates krb5_config.h, which
contains the preprocessor macros that need to be defined in the Kerberos
case and undefined otherwise.
Approved by: re (marius)
I have worked hard to reduce diffs against the vendor branch. One
notable change in that respect is that we no longer prefer DSA over
RSA - the reasons for doing so went away years ago. This may cause
some surprises, as ssh will warn about unknown host keys even for
hosts whose keys haven't changed.
MFC after: 6 weeks
