Rename TARGET_OS_* to HOST_OS_*.

runtime/bin/platform_macos.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_MACOS)
+#if defined(HOST_OS_MACOS)
 
 #include "bin/platform.h"
 
-#if !TARGET_OS_IOS
+#if !HOST_OS_IOS
 #include <crt_externs.h>  // NOLINT
-#endif                    // !TARGET_OS_IOS
+#endif                    // !HOST_OS_IOS
 #include <mach-o/dyld.h>
 #include <signal.h>      // NOLINT
 #include <string.h>      // NOLINT
 #include <sys/sysctl.h>  // NOLINT
 #include <sys/types.h>   // NOLINT
 #include <unistd.h>      // NOLINT
 
 #include "bin/fdutils.h"
 #include "bin/file.h"
 
@@ skipping 50 matching lines @@
   if (sysctlbyname("hw.logicalcpu", &cpus, &cpus_length, NULL, 0) == 0) {
     return cpus;
   } else {
     // Failed, fallback to using sysconf.
     return sysconf(_SC_NPROCESSORS_ONLN);
   }
 }
 
 
 const char* Platform::OperatingSystem() {
-#if TARGET_OS_IOS
+#if HOST_OS_IOS
   return "ios";
 #else
   return "macos";
 #endif
 }
 
 
 const char* Platform::LibraryPrefix() {
   return "lib";
 }
 
 
 const char* Platform::LibraryExtension() {
   return "dylib";
 }
 
 
 bool Platform::LocalHostname(char* buffer, intptr_t buffer_length) {
   return gethostname(buffer, buffer_length) == 0;
 }
 
 
 char** Platform::Environment(intptr_t* count) {
-#if TARGET_OS_IOS
+#if HOST_OS_IOS
   // TODO(zra,chinmaygarde): On iOS, environment variables are seldom used. Wire
   // this up if someone needs it. In the meantime, we return an empty array.
   char** result;
   result = reinterpret_cast<char**>(Dart_ScopeAllocate(1 * sizeof(*result)));
   if (result == NULL) {
     return NULL;
   }
   result[0] = NULL;
   *count = 0;
   return result;
@@ skipping 41 matching lines @@
 }
 
 
 void Platform::Exit(int exit_code) {
   exit(exit_code);
 }
 
 }  // namespace bin
 }  // namespace dart
 
-#endif  // defined(TARGET_OS_MACOS)
+#endif  // defined(HOST_OS_MACOS)