So, in general, I think picking a single event backend should be fine. Most applications work with all event backends; krb5 certainly does.
I'm fairly uncomfortable with the idea of using an extension package namespace here though because it seems like you'll need to break this cycle on every new bootstrap, and so it seems like you want something that can be auto-detected or similar. krb5 took a patch for a stage1 build profile to avoid ldap and libsasl. It seems like it's desirable to update both krb5 and libvirto to something modern that makes sense, whatever that is. I have not been following any of this particularly closely. --Sam
