ext/sockets: adding BSD IP_BINDANY constant.

Simply allows the socket to bind to any address, including one not
bound to any network interface.

Author: devnexen

ext/sockets/sockets.stub.php

@@ -1908,6 +1908,13 @@
  */
 const TCP_REPAIR = UNKNOWN;
 #endif
+#if defined(IP_BINDANY)
+/**
+ * @var int
+ * @cvalue IP_BINDANY
+ */
+const IP_BINDANY = UNKNOWN;
+#endif
 #if defined(IP_DONTFRAG)
 /**
  * @var int