[NaCl SDK] Upate atomic ops in nacl_io

native_client_sdk/src/libraries/nacl_io/kernel_handle.h

Index: native_client_sdk/src/libraries/nacl_io/kernel_handle.h
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_handle.h b/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
index 64ef8abd15f3254ef72655b43eda35b9d041d6f4..201fbd9089fcb8d9c9b7ab50285ae6f06c4f9902 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
@@ -15,6 +15,7 @@
 #include "sdk_util/macros.h"
 #include "sdk_util/ref_object.h"
 #include "sdk_util/scoped_ref.h"
+#include "sdk_util/simple_lock.h"
 
 // KernelHandle provides a reference counted container for the open
 // file information, such as it's mount, node, access type and offset.
@@ -33,7 +34,9 @@ class KernelHandle : public RefObject {
   ScopedRef<MountNode> node_;
   size_t offs_;
 
- private:
+private:
+  SimpleLock lock_;
+
   friend class KernelProxy;
   DISALLOW_COPY_AND_ASSIGN(KernelHandle);
 };