The sendmail distribution contains the the following line in
FEATURE(virtusertable',` -o /etc/mail/virtusertable')
:which needs a ` here. This causes the resulting file to be
usable, but missing virtusertable functionality, as well as
a few other things that the file contains that get left out
after the parsing error.
After working with the server I believe this line must further be
FEATURE(`virtusertable', `hash -o /etc/mail/virtusers')
so that sendmail knows what class the virtusers map is, not having
this keeps the server from starting.
Fixed in 8.9.3-8