Fix builds on Mac: icount_ is intptr_t.

runtime/vm/simulator_arm64.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 <setjmp.h>
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM64)
 
@@ skipping 3269 matching lines @@
   } else {
     UnimplementedInstruction(instr);
   }
 }
 
 
 // Executes the current instruction.
 void Simulator::InstructionDecode(Instr* instr) {
   pc_modified_ = false;
   if (IsTracingExecution()) {
-    OS::Print("%"Pu64" ", icount_);
+    OS::Print("%" Pd " ", icount_);
     const uword start = reinterpret_cast<uword>(instr);
     const uword end = start + Instr::kInstrSize;
     Disassembler::Disassemble(start, end);
   }
 
   if (instr->IsDPImmediateOp()) {
     DecodeDPImmediate(instr);
   } else if (instr->IsCompareBranchOp()) {
     DecodeCompareBranch(instr);
   } else if (instr->IsLoadStoreOp()) {
@@ skipping 184 matching lines @@
   set_register(NULL, kExceptionObjectReg, bit_cast<int64_t>(raw_exception));
   set_register(NULL, kStackTraceObjectReg, bit_cast<int64_t>(raw_stacktrace));
   buf->Longjmp();
 }
 
 }  // namespace dart
 
 #endif  // !defined(HOST_ARCH_ARM64)
 
 #endif  // defined TARGET_ARCH_ARM64