Add reusePort argument to ServerSocket.

runtime/bin/socket.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef BIN_SOCKET_H_
 #define BIN_SOCKET_H_
 
 #include "bin/builtin.h"
 #include "bin/utils.h"
 #include "bin/dartutils.h"
@@ skipping 202 matching lines @@
   static intptr_t Accept(intptr_t fd);
 
   // Returns a positive integer if the call is successful. In case of failure
   // it returns:
   //
   //   -1: system error (errno set)
   //   -5: invalid bindAddress
   static intptr_t CreateBindListen(RawAddr addr,
                                    intptr_t port,
                                    intptr_t backlog,
-                                   bool v6_only = false);
+                                   bool v6_only = false,
+                                   bool reuse_port = false);
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(ServerSocket);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_SOCKET_H_