Rename local variable in api.cc to avoid using C++0x keyword thread_local.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index dcf8e17bf3652c7633c772ff8535d8a4fe86d39a..6a3fd2b2b2dfff6f07fbe4f61c976a701cab8845 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -5710,9 +5710,9 @@ void HandleScopeImplementer::Iterate(ObjectVisitor* v) {
 
 
 char* HandleScopeImplementer::Iterate(ObjectVisitor* v, char* storage) {
-  HandleScopeImplementer* thread_local =
+  HandleScopeImplementer* scope_implementer =
       reinterpret_cast<HandleScopeImplementer*>(storage);
-  thread_local->IterateThis(v);
+  scope_implementer->IterateThis(v);
   return storage + ArchiveSpacePerThread();
 }