Probe for wireless interfaces using sysctl.

In FreeBSD HEAD, raw wireless devices don't show up in `ifconfig`.
Expose to OPNSense the wireless devices as per the net.wlan.devices
sysctl.

Signed-off-by:	Shawn Webb <shawn.webb@hardenedbsd.org>

src/etc/inc/interfaces.lib.inc

@@ -47,6 +47,21 @@ function legacy_interface_listget($flag = '')
         $ifs = explode(' ', $out[0]);
     }
 
+	/*
+	 * If we are running -CURRENT, wireless devices are exposed
+	 * via the sysctl net.wlan.devices.
+	 */
+	unset($out);
+	unset($ret);
+	exec('/sbin/sysctl -n net.wlan.devices', $out, $ret);
+	if ($ret) {
+		return ($ifs);
+	}
+
+	foreach (explode(' ', trim($out[0])) as $wlandev) {
+		$ifs[] = $wlandev;
+	}
+
     return ($ifs);
 }