New sendmail.mc, spamass-milter requirement?

[Dan Thurman <dant cdkkt com>]

I got this wierd maillog message:

Mar 31 18:00:31 <hostname> spamass-milter[2818]: Could not retrieve
sendmail macro "b"!.  Please add it to confMILTER_MACROS_ENVRCPT for
better spamassassin results

Can someone point me to what I need to add, if anything to the mc file?

Thanks!