Allow compiling with strict aliasing enabled on GCC 4.4.

src/top.cc

Index: src/top.cc
diff --git a/src/top.cc b/src/top.cc
index 2887b7664fd5a10744c131ec80766bcba3201dfb..1a4a9485d17ee9f5754cf268df6d3606ddb1f214 100644
--- a/src/top.cc
+++ b/src/top.cc
@@ -107,16 +107,15 @@ void Top::IterateThread(ThreadVisitor* v, char* t) {
 void Top::Iterate(ObjectVisitor* v, ThreadLocalTop* thread) {
   v->VisitPointer(&(thread->pending_exception_));
   v->VisitPointer(&(thread->pending_message_obj_));
-  v->VisitPointer(
-      BitCast<Object**, Script**>(&(thread->pending_message_script_)));
-  v->VisitPointer(BitCast<Object**, Context**>(&(thread->context_)));
+  v->VisitPointer(BitCast<Object**>(&(thread->pending_message_script_)));
+  v->VisitPointer(BitCast<Object**>(&(thread->context_)));
   v->VisitPointer(&(thread->scheduled_exception_));
 
   for (v8::TryCatch* block = thread->TryCatchHandler();
        block != NULL;
        block = TRY_CATCH_FROM_ADDRESS(block->next_)) {
-    v->VisitPointer(BitCast<Object**, void**>(&(block->exception_)));
-    v->VisitPointer(BitCast<Object**, void**>(&(block->message_)));
+    v->VisitPointer(BitCast<Object**>(&(block->exception_)));
+    v->VisitPointer(BitCast<Object**>(&(block->message_)));
   }
 
   // Iterate over pointers on native execution stack.