by erickheit@dyn.com:

% go version
go version go1.3 freebsd/amd64
% uname -v
FreeBSD 9.1-RELEASE #0 r243825: Tue Dec  4 09:23:10 UTC 2012
root@farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC

syslog.New() correctly finds the syslog unix-domain socket on linux, but not
on freebsd. On my (somewhat out-of-date) freebsd system, the code below gives
the less-than-helpful message: "Unix syslog delivery error"

It looks like a simple fix is to add "/var/run/log" to the logPaths list in
src/pkg/log/syslog/syslog_unix.go

The workaround, of course, is to call
    syslog.Dial("unixgram", "/var/run/log",...)
instead, but that's not terribly portable.

Here's a trivial test program:

package main
import "log/syslog"
import "fmt"
import "os"

func main() {
    slog, err := syslog.New(syslog.LOG_DAEMON, "stuff")
    if err != nil {
        fmt.Fprintln(os.Stderr, "syslog.New failed: ", err)
    }
    slog.Info("can you see me logging?")
}