Hi Martin, thanks for the reply!
The work-around could be to install the package with force.
How would I do that? Isn't a part of the problem, that one package needs a symlink at the same place where an other package needs to place a directory? Wouldn't installing by force destroy the apt-system? The problem is, that all packages depend on libc6 (obviously) and no new software will be installable via the apt-system. You will always get a "unmet dependencies" error.
Fixing the bug may take days, months, or years.
This raises the question why to use debian on a sparc system in the first place. This is a serious bug and apparently nobody want's to fix it. If I'd be able to do so I would, but I'm not. I am using debian on many sparc-systems. If this problem persists, I will have to move to an other distri. This is something I do not want at all. My company is very connected to the debian project (we are hosting a debian related cvs-server and mirror the exim website in germany), and I like the debian way of package management and the distiction between the stable, testing and unstable branches. What I want to say is: Please! Somebody fix this!
Thanks and best wishes Felix