Rename TARGET_OS_* to HOST_OS_*.

runtime/bin/directory_win.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.
 
 #include "platform/globals.h"
-#if defined(TARGET_OS_WINDOWS)
+#if defined(HOST_OS_WINDOWS)
 
 #include "bin/directory.h"
 #include "bin/file.h"
 #include "bin/utils.h"
 #include "bin/utils_win.h"
 
 #include <errno.h>     // NOLINT
 #include <sys/stat.h>  // NOLINT
 
 #include "bin/dartutils.h"
@@ skipping 486 matching lines @@
   }
   DWORD flags = MOVEFILE_WRITE_THROUGH;
   int move_status =
       MoveFileExW(system_path.wide(), system_new_path.wide(), flags);
   return (move_status != 0);
 }
 
 }  // namespace bin
 }  // namespace dart
 
-#endif  // defined(TARGET_OS_WINDOWS)
+#endif  // defined(HOST_OS_WINDOWS)