A log file name may now be prefixed by a '-' if it should not be
explicitly fsynced after kernel messages are logged. This option
should be syntax compatible with a similar option in Linux syslogd.

I've made some small changes to Pekka's patch, hoepfully I haven't
goofed anything.

PR: 66790
Submitted by: Pekka Savola <pekkas@netcore.fi>
Obtained from: Martin Schulze's syslogd
MFC after: 1 month