[syslog-ng] Question about syntax for source

[Phusion]

In syslog-ng 2.x versions under OpenBSD I used to use the following
line for a source.

source local { internal(); pipe("/dev/klog" log_prefix("kernel: "));
unix-dgram("/dev/log"); };

When trying to convert this for syslog-ng 3.x under OpenBSD. I have an
error. When I use syslog-ng -s -f ../syslog-ng.conf it works, but when
I run syslog-ng -p /var/run/syslog-ng.pid, I get the following error.

# /usr/local/sbin/syslog-ng -p /var/run/syslog-ng.pid
WARNING: you are using the pipe driver, underlying file is not a FIFO,
it should be used by file(); filename='/dev/klog'

Here is the current source line using syslog-ng 3.0 under OpenBSD 4.8.

source local { internal(); pipe("/dev/klog" program_override("kernel:
")); unix-dgram("/dev/log"); };

Please advise.

Phusion