Fix non-ia32 build.

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index b3f3b4b14020eb97daf391e2a95a8d9ce5ab1d00..3a90343b844998253fe4f498e9b2051be008a65b 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -40,12 +40,15 @@
 namespace v8 {
 namespace internal {
 
-MacroAssembler::MacroAssembler(void* buffer, int size)
-    : Assembler(Isolate::Current(), buffer, size),
+MacroAssembler::MacroAssembler(Isolate* arg_isolate, void* buffer, int size)
+    : Assembler(arg_isolate, buffer, size),
       generating_stub_(false),
       allow_stub_calls_(true),
-      root_array_available_(true),
-      code_object_(isolate()->heap()->undefined_value()) {
+      root_array_available_(true) {
+  if (isolate() != NULL) {
+    code_object_ = Handle<Object>(isolate()->heap()->undefined_value(),
+                                  isolate());
+  }
 }
 
 
@@ -2885,7 +2888,9 @@ void MacroAssembler::CallCFunction(Register function, int num_arguments) {
 
 
 CodePatcher::CodePatcher(byte* address, int size)
-    : address_(address), size_(size), masm_(address, size + Assembler::kGap) {
+    : address_(address),
+      size_(size),
+      masm_(Isolate::Current(), address, size + Assembler::kGap) {
   // Create a new macro assembler pointing to the address of the code to patch.
   // The size is adjusted with kGap on order for the assembler to generate size
   // bytes of instructions without failing with buffer size constraints.