Rename TARGET_OS_* to HOST_OS_*.

runtime/bin/stdio_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.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
-#if defined(TARGET_OS_WINDOWS)
+#if defined(HOST_OS_WINDOWS)
 
 #include "bin/stdio.h"
 
 namespace dart {
 namespace bin {
 
 bool Stdin::ReadByte(int* byte) {
   HANDLE h = GetStdHandle(STD_INPUT_HANDLE);
   uint8_t buffer[1];
   DWORD read = 0;
@@ skipping 70 matching lines @@
     return false;
   }
   size[0] = info.srWindow.Right - info.srWindow.Left + 1;
   size[1] = info.srWindow.Bottom - info.srWindow.Top + 1;
   return true;
 }
 
 }  // namespace bin
 }  // namespace dart
 
-#endif  // defined(TARGET_OS_WINDOWS)
+#endif  // defined(HOST_OS_WINDOWS)
 
 #endif  // !defined(DART_IO_DISABLED)