Rename TARGET_OS_* to HOST_OS_*.

runtime/lib/double.cc

 // Copyright (c) 2011, 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/bootstrap_natives.h"
 
 #include "platform/math.h"
 
 #include "vm/code_generator.h"  // DartModulo.
 #include "vm/dart_entry.h"
@@ skipping 180 matching lines @@
   return Double::New(ceil(arg.value()));
 }
 
 
 DEFINE_NATIVE_ENTRY(Double_truncate, 1) {
   const Double& arg = Double::CheckedHandle(arguments->NativeArgAt(0));
   return Double::New(trunc(arg.value()));
 }
 
 
-#if defined(TARGET_OS_MACOS)
+#if defined(HOST_OS_MACOS)
 // MAC OSX math library produces old style cast warning.
 #pragma GCC diagnostic ignored "-Wold-style-cast"
 #endif
 
 DEFINE_NATIVE_ENTRY(Double_toInt, 1) {
   const Double& arg = Double::CheckedHandle(arguments->NativeArgAt(0));
   return DoubleToInteger(arg.value(), "Infinity or NaN toInt");
 }
 
 
@@ skipping 97 matching lines @@
 DEFINE_NATIVE_ENTRY(Double_flipSignBit, 1) {
   const Double& arg = Double::CheckedHandle(arguments->NativeArgAt(0));
   const double in_val = arg.value();
   const int64_t bits = bit_cast<int64_t, double>(in_val) ^ kSignBitDouble;
   return Double::New(bit_cast<double, int64_t>(bits));
 }
 
 // Add here only functions using/referring to old-style casts.
 
 }  // namespace dart