Rename TARGET_OS_* to HOST_OS_*.

runtime/vm/cpuinfo_win.cc

 // Copyright (c) 2014, 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 "vm/globals.h"
-#if defined(TARGET_OS_WINDOWS)
+#if defined(HOST_OS_WINDOWS)
 
 #include "vm/cpuinfo.h"
 #include "vm/cpuid.h"
 
 // __cpuid()
 #include <intrin.h>  // NOLINT
 #include <string.h>  // NOLINT
 
 #include "platform/assert.h"
 
@@ skipping 36 matching lines @@
 bool CpuInfo::HasField(const char* field) {
   ASSERT(method_ != kCpuInfoDefault);
   return (strcmp(field, fields_[kCpuInfoProcessor]) == 0) ||
          (strcmp(field, fields_[kCpuInfoModel]) == 0) ||
          (strcmp(field, fields_[kCpuInfoHardware]) == 0) ||
          (strcmp(field, fields_[kCpuInfoFeatures]) == 0);
 }
 
 }  // namespace dart
 
-#endif  // defined(TARGET_OS_WINDOWS)
+#endif  // defined(HOST_OS_WINDOWS)