In order to enable Kerberos 4 support, I have to edit the ebuild to include --with-krb4=/usr (similar to what the kerberos use flag does). I suggest adding a krb4 use flag that enables this option. Reproducible: Always Steps to Reproduce: 1. 2. 3.
Added support for 'krb4' in evolution-2.2.3-r1. Thanks for reporting this issue.