Hello heisenbug, not being able to manually reproduce the issue suddenly the bug 
also disappeared in Jenkins environment. Closing until I can reproduce it again.

Our current daily ISO builds against Debian/sid fail to build:

  http://jenkins.grml.org/job/grml32-full_sid/438/console
  http://jenkins.grml.org/job/grml64-full_sid/437/console

due to the following problem:

| Selecting previously unselected package fuse.
| Unpacking fuse (from .../archives/fuse_2.9.2-4_i386.deb) ...
| Processing triggers for man-db ...
| Setting up libfuse2:i386 (2.9.2-4) ...
| Setting up makedev (2.3.1-92) ...
| /run/udev or .udevdb or .udev presence implies active udev.  Aborting MAKEDEV invocation.
| /run/udev or .udevdb or .udev presence implies active udev.  Aborting MAKEDEV invocation.
| /run/udev or .udevdb or .udev presence implies active udev.  Aborting MAKEDEV invocation.
| Setting up fuse (2.9.2-4) ...
| Creating fuse group...
| Adding group `fuse' (GID 104) ...
| Done.
| Creating fuse device...
| /run/udev or .udevdb or .udev presence implies active udev.  Aborting MAKEDEV invocation.
| chown: cannot access `/dev/fuse': No such file or directory
| dpkg: error processing fuse (--configure):
|  subprocess installed post-installation script returned error exit status 1
| Errors were encountered while processing:
|  fuse
| E: Sub-process /usr/bin/dpkg returned an error code (1)

I've already reported this issue once to Debian's BTS against the fuse package:

  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=696055

but I wasn't able to reproduce this issue back then.
I also can't reproduce this when manually creating a chroot today, so this
seems to be a bit more tricky and really caused by the fact that the chroot
looks like it has a running udev agent.

We need to solve this to make sure it doesn't reach Debian/testing.