Sendmail SMTP AUTH no longer works

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

I've upgraded to pkgsrc-2022Q1 and now SMTP AUTH no longer works. This 
upgrades all the cyrus stuff to 2.1.28 from 2.1.27 as well as revbumping 
sendmail 8.16.1. The configuration files have not changed and yes, I'm 
installing the cy2-plain, etc. plugins.

I've found that if I revert to my previous pkg set and then upgrade just 
the cyrus components to 2.1.28, then it still works. If I upgrade sendmail 
from 8.16.1 to 8.16.1nb1 (which also requires me to force upgrade 
openldap-client) then this stops AUTH working (whichever version of the 
cyrus components are in place).

I've tried to use ktrace to work out what's happening, but sendmail seems 
to be successfully opening the various sasl files and I don't see any 
obvious differences between the good and bad traces. Any ideas on how to 
debug this?

--
Stephen