Don't use AI_V4MAPPED.

runtime/bin/socket_win.cc

 // 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.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/builtin.h"
 #include "bin/eventhandler.h"
 #include "bin/file.h"
@@ skipping 215 matching lines @@
   Initialize();
 
   // getaddrinfo is not thread-safe on Windows. Use a mutex to get around it.
   MutexLocker locker(getaddrinfo_mutex);
 
   // Perform a name lookup for a host name.
   struct addrinfo hints;
   memset(&hints, 0, sizeof(hints));
   hints.ai_family = SocketAddress::FromType(type);
   hints.ai_socktype = SOCK_STREAM;
-  hints.ai_flags = (AI_V4MAPPED | AI_ADDRCONFIG);
+  hints.ai_flags = AI_ADDRCONFIG;
   hints.ai_protocol = IPPROTO_TCP;
   struct addrinfo* info = NULL;
   int status = getaddrinfo(host, 0, &hints, &info);
   if (status != 0) {
     // We failed, try without AI_ADDRCONFIG. This can happen when looking up
     // e.g. '::1', when there are no global IPv6 addresses.
-    hints.ai_flags = AI_V4MAPPED;
+    hints.ai_flags = 0;
     status = getaddrinfo(host, 0, &hints, &info);
   }
   if (status != 0) {
     ASSERT(*os_error == NULL);
     DWORD error_code = WSAGetLastError();
     SetLastError(error_code);
     *os_error = new OSError();
     return NULL;
   }
   intptr_t count = 0;
@@ skipping 393 matching lines @@
                     proto,
                     MCAST_LEAVE_GROUP,
                     reinterpret_cast<char *>(&mreq),
                     sizeof(mreq)) == 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)