I have integrated part of Peter's patch into the CVS repository. I've reviewed the UDP listen part of it and adopted that part to some internal specifics of rsyslog. This version is currently available via anonymous CVS on sourceforge. I recommend having a look at it.
The CVS version should not be used to build production versions. There are eventually some issues in the client part of the code. I'll review them together with Peter soon.
I would like to thank Peter very much - without his help, I'd never taken the route to integrate IPv6. Now it looks quite easy and even elegant.
Please note that there will be one exception (at least for the time being): rfc3195d will continue to be IPv4 only, as there is nobody using RFC 3195. Supporting IPv6 would require modifying liblogging, which is not to happen without some real demand
Rainer