cmd/syncthing: Fix -logfile/-no-restart test on non-Windows.

cmd/syncthing/main.go

@@ -320,9 +320,11 @@ func main() {
 		os.Setenv("STGUIAPIKEY", options.guiAPIKey)
 	}
 
-	// Check for options which are not compatible with each other
-	// Have to check logfile before it's set to the default below - we only want to complain if they set -logfile explicitly, not if it's set to its default location
-	if options.noRestart && options.logFile != "" {
+	// Check for options which are not compatible with each other. We have
+	// to check logfile before it's set to the default below - we only want
+	// to complain if they set -logfile explicitly, not if it's set to its
+	// default location
+	if options.noRestart && (options.logFile != "" && options.logFile != "-") {
 		l.Fatalln("-logfile may not be used with -no-restart or STNORESTART")
 	}