Fix problem building on Ubuntu Natty

Change-Id: Ib42ae0dcbccc2ae26c6834ef1762227c05c51a82
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/lib/ExecutionEngine/Script.cpp b/lib/ExecutionEngine/Script.cpp
index 7aa3748..afcc0ea 100644
--- a/lib/ExecutionEngine/Script.cpp
+++ b/lib/ExecutionEngine/Script.cpp
@@ -686,7 +686,7 @@
   case ScriptStatus::Compiled:  return mCompiled->getELFSize();
 
   default:
-    return NULL;
+    return 0;
   }
   return 0;
 }