Fix build breaks on iOS. Adds missing import and avoid use of unavailable macro.

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)
+#include <sys/sysctl.h>
+#endif
 
 #include "platform/utils.h"
 #include "vm/isolate.h"
 #include "vm/zone.h"
 
 namespace dart {
 
 const char* OS::Name() {
   return "macos";
 }
@@ skipping 56 matching lines @@
 
 int64_t OS::GetCurrentTraceMicros() {
 #if defined(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, arraysize(mib), &boottime, &size, NULL, 0);
+  int kr = sysctl(mib, sizeof(mib) / sizeof(mib[0]), &boottime, &size, NULL, 0);
   ASSERT(KERN_SUCCESS == kr);
   int64_t now = GetCurrentTimeMicros();
   int64_t origin = boottime.tv_sec * kMicrosecondsPerSecond;
   origin += boottime.tv_usec;
   return now - origin;
 #else
   static mach_timebase_info_data_t timebase_info;
   if (timebase_info.denom == 0) {
     // Zero-initialization of statics guarantees that denom will be 0 before
     // calling mach_timebase_info.  mach_timebase_info will never set denom to
@@ skipping 230 matching lines @@
 }
 
 
 void OS::Exit(int code) {
   exit(code);
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)