Treat EAGAIN/EWOULDBLOCK as requests for retry on socket accept.

runtime/bin/socket_impl.dart

 // Copyright (c) 2012, 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.
 
 
 class _SocketBase {
   // Bit flags used when communicating between the eventhandler and
   // dart code. The EVENT flags are used to indicate events of
   // interest when sending a message from dart code to the
   // eventhandler. When receiving a message from the eventhandler the
@@ skipping 274 matching lines @@
     _setHandler(_IN_EVENT,
                 _clientConnectionHandler != null ? _connectionHandler : null);
   }
 
   void _connectionHandler() {
     if (_id >= 0) {
       _Socket socket = new _Socket._internal();
       var result = _accept(socket);
       if (result is OSError) {
         _reportError(result, "Accept failed");
+      } else if (result) {
+        _clientConnectionHandler(socket);
       } else {
-        _clientConnectionHandler(socket);
+        // Temporary failure accepting the connection. Ignoring
+        // temporary failures lets us retry when we wake up with data
+        // on the listening socket again.
       }
     }
   }
 
   bool _isListenSocket() => true;
   bool _isPipe() => false;
 
   var _clientConnectionHandler;
 }
 
@@ skipping 247 matching lines @@
   }
 
   bool _seenFirstOutEvent = false;
   bool _pipe = false;
   Function _clientConnectHandler;
   Function _clientWriteHandler;
   SocketInputStream _inputStream;
   SocketOutputStream _outputStream;
   static SendPort _socketService;
 }