- validate the two hex chars in replace_chars \x

 - test (now fixed) /dev/tape/ links

 - /run/udev/control socket
   (add ConditionVirtualization=!pidns)

 - move udevd -> --libexecdir

 - have a $attrs{} ?

 - kill rules_generator

 - move udevadm -> --bindir

 - kill tabs?

 - warn about RUN+="socket:"

 - libudev.so.1 with symbol versioning:
     - return object with *_unref()
     - udev_monitor_from_socket()