Magicfilter should log non-existent dependent files in syslog.  e.g.
when trying to print and gs, enscript or similar are not installed on
the system, magicfilter should log a message "Magicfilter: trying to
print to /usr/bin/gs which is not present".  Given that it's in the
middle of the lpd chain normal error messages get lost, which makes
debugging setup hard.