[exim] X-Spam-Report for Clean messages

I have a need for more detail in my log. We are using exim as an
inbound relay and pre-filtering before delivering to our mail system.

The reject.log file is very useful but would be more helpful if it had
CLEAN messages logged also. Now obviously CLEAN messages should not be
part of reject.log so the best solution would be a log just for
X-Spam-Report (SPAM and CLEAN)

Searching for these terms is pretty rough since they are in so many conf
files uploaded....

--snip--
warn   add_header = X-Spam-Score: $spam_score ($spam_bar)\n\
            X-Spam-Report: $spam_report
deny    condition = ${if >{$spam_score_int}{90} {1}}
            message   = Your message was RejecteD as Spam
accept
--snip--

I know log size will increase, but I do not expect the logs to grow more
than %33 considering yesterday we
rejected 167,000 Unknown User
rejected 133,000 spam
and
delivered 91,000 messages