I added 'spf' use flag to postfix-2.2.10. There's no error with this patch & it works fine! http://www.linuxrulz.org/nkukard/postfix/postfix-2.2.10_libspf2-1.2.x-20060614.patch.gz
Created attachment 91685 [details, diff] mail-mta/postfix-2.1.10.ebuild
There's really no need for patches, you can use policy daemon plugin w/ postfix. *** This bug has been marked as a duplicate of 62756 ***