This should also address:
On Tue, Nov 3, 2009 at 16:21, Marco d'Itri <md@linux.it> wrote:
> udev_rules_new() in udev/udev-rules.c unconditionally creates the
> directory.
> This is a problem because the function is called also by e.g. udevadm
> test, and creating /dev/.udev/ when it does not exist is an unacceptable
> side effect which will break everything else that checks for its
> existence to know if udev is running.
081be002ea