Some build file cleanup

runtime/bin/secure_socket_unsupported.cc

 // 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.
 
+#if defined(DART_IO_SECURE_SOCKET_DISABLED)
+
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 
 #include "include/dart_api.h"
 
 namespace dart {
 namespace bin {
 
 void FUNCTION_NAME(SecureSocket_Init)(Dart_NativeArguments args) {
   Dart_ThrowException(DartUtils::NewDartArgumentError(
@@ skipping 153 matching lines @@
  public:
   static CObject* ProcessFilterRequest(const CObjectArray& request);
 };
 
 CObject* SSLFilter::ProcessFilterRequest(const CObjectArray& request) {
   return CObject::IllegalArgumentError();
 }
 
 }  // namespace bin
 }  // namespace dart
+
+#endif  // defined(DART_IO_SECURE_SOCKET_DISABLED)