when i try to
emerge -auvD world
or
emerge -auvD postfix
i get the
These are the packages that would be merged, in order:
Calculating dependencies... done!
[ebuild U ] mail-mta/postfix-2.3.2 [2.2.10-r20] USE="ipv6 ldap mailwrapper mysql pam sasl ssl -cdb% -dovecot-sasl% -hardened -mbox -nis -postgres -vda" 0 kB
Total size of downloads: 0 kB
portage try to merge postfix from portage, and not from layman overlay :-(