Fix missing global declarations in socket_unsupported.cc

runtime/bin/socket_unsupported.cc

 // Copyright (c) 2016, 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.
 
 #if defined(DART_IO_DISABLED)
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "include/dart_api.h"
 
 namespace dart {
 namespace bin {
 
+bool short_socket_read = false;
+
+bool short_socket_write = false;
+
 void FUNCTION_NAME(InternetAddress_Parse)(Dart_NativeArguments args) {
   Dart_ThrowException(DartUtils::NewDartArgumentError(
       "Sockets unsupported on this platform"));
 }
 
 
 void FUNCTION_NAME(NetworkInterface_ListSupported)(Dart_NativeArguments args) {
   Dart_ThrowException(DartUtils::NewDartArgumentError(
       "Sockets unsupported on this platform"));
 }
@@ skipping 127 matching lines @@
 
 void FUNCTION_NAME(Socket_LeaveMulticast)(Dart_NativeArguments args) {
   Dart_ThrowException(DartUtils::NewDartArgumentError(
       "Sockets unsupported on this platform"));
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(DART_IO_DISABLED)