Fix clang builds.

runtime/vm/become.cc

 // Copyright (c) 2016, 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/become.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 
 #include "vm/dart_api_state.h"
@@ skipping 134 matching lines @@
   int count_;
 
   DISALLOW_COPY_AND_ASSIGN(ForwardHeapPointersHandleVisitor);
 };
 
 
 // On IA32, object pointers are embedded directly in the instruction stream,
 // which is normally write-protected, so we need to make it temporarily writable
 // to forward the pointers. On all other architectures, object pointers are
 // accessed through ObjectPools.
+#if defined(TARGET_ARCH_IA32)
 class WritableCodeLiteralsScope : public ValueObject {
  public:
   explicit WritableCodeLiteralsScope(Heap* heap) : heap_(heap) {
-#if defined(TARGET_ARCH_IA32)
     if (FLAG_write_protect_code) {
       heap_->WriteProtectCode(false);
     }
-#endif
   }
 
   ~WritableCodeLiteralsScope() {
-#if defined(TARGET_ARCH_IA32)
     if (FLAG_write_protect_code) {
       heap_->WriteProtectCode(true);
     }
-#endif
   }
 
  private:
   Heap* heap_;
 };
+#else
+class WritableCodeLiteralsScope : public ValueObject {
+ public:
+  explicit WritableCodeLiteralsScope(Heap* heap) { }
+  ~WritableCodeLiteralsScope() { }
+};
+#endif
 
 
 void Become::MakeDummyObject(const Instance& instance) {
   // Make the forward pointer point to itself.
   // This is needed to distinguish it from a real forward object.
   ForwardObjectTo(instance.raw(), instance.raw());
 }
 
 
 static bool IsDummyObject(RawObject* object) {
@@ skipping 69 matching lines @@
   }
 
 #if defined(DEBUG)
   for (intptr_t i = 0; i < before.Length(); i++) {
     ASSERT(before.At(i) == after.At(i));
   }
 #endif
 }
 
 }  // namespace dart