what to do with *.rpmnew files?

[Don Russell <fedora@xxxxxxxxxxxxxxxxxxxxx>]

Today I updated sendmail via yum and received a warning that 
/etc/mail/sendmail.mc was created as /etc/mail/sendmail.mc.rpmnew.

(A few other files had the same warning, but they are created from the 
.mc file so I'm not too concerned.)

I gather this happens because I changed the sendmail.mc file so the 
update process doesn't want to wipe out my changes.

Are there any tools to compare/apply the differences between the rpmnew 
version and my current version? Or, do I have to do something like run 
diff and then go through all the changes one by one manually?

Thanks,
Don