Use #if TARGET_OS_IOS instead of #ifdef TARGET_OS_IOS.

runtime/vm/os_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 "vm/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include "vm/os.h"
 
 #include <errno.h>  // NOLINT
 #include <limits.h>  // NOLINT
 #include <mach/mach.h>  // NOLINT
 #include <mach/clock.h>  // NOLINT
 #include <mach/mach_time.h>  // NOLINT
 #include <sys/time.h>  // NOLINT
 #include <sys/resource.h>  // NOLINT
 #include <unistd.h>  // NOLINT
-#if defined(TARGET_OS_IOS)
+#if TARGET_OS_IOS
 #include <sys/sysctl.h>
 #endif
 
 #include "platform/utils.h"
 #include "vm/isolate.h"
 #include "vm/zone.h"
 
 namespace dart {
 
 const char* OS::Name() {
@@ skipping 50 matching lines @@
   struct timeval tv;
   if (gettimeofday(&tv, NULL) < 0) {
     UNREACHABLE();
     return 0;
   }
   return (static_cast<int64_t>(tv.tv_sec) * 1000000) + tv.tv_usec;
 }
 
 
 int64_t OS::GetCurrentTraceMicros() {
-#if defined(TARGET_OS_IOS)
+#if TARGET_OS_IOS
   // On iOS mach_absolute_time stops while the device is sleeping. Instead use
   // now - KERN_BOOTTIME to get a time difference that is not impacted by clock
   // changes. KERN_BOOTTIME will be updated by the system whenever the system
   // clock change.
   struct timeval boottime;
   int mib[2] = {CTL_KERN, KERN_BOOTTIME};
   size_t size = sizeof(boottime);
   int kr = sysctl(mib, sizeof(mib) / sizeof(mib[0]), &boottime, &size, NULL, 0);
   ASSERT(KERN_SUCCESS == kr);
   int64_t now = GetCurrentTimeMicros();
@@ skipping 11 matching lines @@
     kern_return_t kr = mach_timebase_info(&timebase_info);
     ASSERT(KERN_SUCCESS == kr);
   }
 
   // timebase_info converts absolute time tick units into nanoseconds.  Convert
   // to microseconds.
   int64_t result = mach_absolute_time() / kNanosecondsPerMicrosecond;
   result *= timebase_info.numer;
   result /= timebase_info.denom;
   return result;
-#endif  // defined(TARGET_OS_IOS)
+#endif  // TARGET_OS_IOS
 }
 
 
 void* OS::AlignedAllocate(intptr_t size, intptr_t alignment) {
   const int kMinimumAlignment = 16;
   ASSERT(Utils::IsPowerOfTwo(alignment));
   ASSERT(alignment >= kMinimumAlignment);
   // Temporary workaround until xcode is upgraded.
   // Mac guarantees malloc returns a 16 byte aligned memory chunk.
   // Currently we only allocate with 16-bye alignment.
@@ skipping 206 matching lines @@
 }
 
 
 void OS::Exit(int code) {
   exit(code);
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)