[NaCl SDK]: nacl_io: add nacl_io_uninit function.

native_client_sdk/src/libraries/nacl_io/nacl_io.h

Index: native_client_sdk/src/libraries/nacl_io/nacl_io.h
diff --git a/native_client_sdk/src/libraries/nacl_io/nacl_io.h b/native_client_sdk/src/libraries/nacl_io/nacl_io.h
index a26f39d8b5e8aaee351e0568d81a56f954140525..21abc3463259d422b49bb841c361a5fae59c93c1 100644
--- a/native_client_sdk/src/libraries/nacl_io/nacl_io.h
+++ b/native_client_sdk/src/libraries/nacl_io/nacl_io.h
@@ -51,6 +51,14 @@ void nacl_io_init();
  */
 void nacl_io_init_ppapi(PP_Instance instance, PPB_GetInterface get_interface);
 
+/**
+ * Uninitialize nacl_io.
+ *
+ * This removes interception for POSIX C-library function and releases
+ * any associated resources.
+ */
+void nacl_io_uninit();
+
 void nacl_io_set_exit_callback(nacl_io_exit_callback_t exit_callback,
                                void* user_data);