Milter-greylist

Hi,  New to the list.  

Not having used a milter before, I could only get it to work with 
sendmail.cf, except the greylist part got trashed any time I updated 
sendmail.mc

After hours of searching, maybe in all the wrong places, I found the 
elusive answer that seems to be assumed.  Could this be added to the 
manual to save other people the same frustration?

For those of you who build your .cf from a .mc file with m4, you must 
define:

define(`_FFR_MILTER', `1')dnl. 

Then the mail filter can be defined as: 

INPUT_MAIL_FILTER(`greylist',
`S=local:/var/milter-greylist/milter-greylist.sock')dnl
define(`confMILTER_MACROS_CONNECT', `j, {if_addr}')dnl
define(`confMILTER_MACROS_HELO', `{verify}, {cert_subject}')dnl
define(`confMILTER_MACROS_ENVFROM', `i, {auth_authen}')dnl