Fix arm64 compilation with clang.

src/arm64/disasm-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <assert.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
 
 #include "src/v8.h"
@@ skipping 1779 matching lines @@
   }
 
  private:
   v8::internal::Vector<char> out_buffer_;
 };
 
 Disassembler::Disassembler(const NameConverter& converter)
     : converter_(converter) {}
 
 
-Disassembler::~Disassembler() {}
+Disassembler::~Disassembler() { USE(converter_); }
 
 
 int Disassembler::InstructionDecode(v8::internal::Vector<char> buffer,
                                     byte* instr) {
   v8::internal::Decoder<v8::internal::DispatchingDecoderVisitor> decoder;
   BufferDisassembler disasm(buffer);
   decoder.AppendVisitor(&disasm);
 
   decoder.Decode(reinterpret_cast<v8::internal::Instruction*>(instr));
   return v8::internal::kInstructionSize;
@@ skipping 12 matching lines @@
   decoder.AppendVisitor(&disasm);
 
   for (byte* pc = start; pc < end; pc += v8::internal::kInstructionSize) {
     decoder.Decode(reinterpret_cast<v8::internal::Instruction*>(pc));
   }
 }
 
 }  // namespace disasm
 
 #endif  // V8_TARGET_ARCH_ARM64