[patch] burncd(8) signal and error handling improvements

Hi,

burncd(8) doesn't handle signals and interrupting burncd during
operation for example with SIGINT (^C) may leave the drive spinning and
locked. This may happen also if you try to write a too large image to a
disc and burncd(8) exits with an I/O error.

Attached patch implements signal handling for burncd(8). It does
CDRIOCFLUSH ioctl to attempt leave burner sane state when burning is
interrupted with SIGHUP, SIGINT, SIGTERM or in case an I/O error occurs
during write. Blanking will still continue after interrupt but it seems
to finish correctly even after burncd(8) has quit.

Relevant PR is bin/48730 which has an older version of the patch.

-- 
Jaakko