A wrapper for CUPS backends to make error handling configurable

Usually, if a CUPS backend exits with an error status other than zero
(for example if a printer is not turned on or not reachable on the
network), CUPS disables the print queue and one can only print again
if a system administrator re-enables the queue manually. Even restarting
CUPS (or rebooting) does not re-enable disabled queues.

--- NOTE ---
Since CUPS version 1.2 there should be no longer the need for
the "beh" backend wrapper because CUPS 1.2.x provides the
ErrorPolicy in /etc/cups/printers.conf if the backend fails
with exit code 1 (CUPS_BACKEND_FAILED), see
http://www.cups.org/documentation.php/ref-print…
and http://www.cups.org/documentation.php/man-backe…

Use it by default for backend error handling; use "beh" wrapper
backend only for advanced configuration.

• Michael Shigorin

• beh