Add [AP]F_INET6? variables if the Socket constructor has them.

exec/load/sockdefs.js

@@ -80,6 +80,15 @@ var SOCK_RAW        =3;              /* raw-protocol interface */
 var SOCK_RDM        =4;              /* reliably-delivered message */
 var SOCK_SEQPACKET  =5;              /* sequenced packet stream */
 
+if (Socket.PF_INET !== undefined)
+	var PF_INET = Socket.PF_INET;
+if (Socket.PF_INET6 !== undefined)
+	var PF_INET6 = Socket.PF_INET6;
+if (Socket.AF_INET !== undefined)
+	var AF_INET = Socket.AF_INET;
+if (Socket.AF_INET6 !== undefined)
+	var AF_INET6 = Socket.AF_INET6;
+
 /* Option name parameter to Socket.getoption/setoption */
 var sockopts = [
 	"TYPE",