diff --git a/include/lib/libc/aarch64/stdio_.h b/include/lib/libc/aarch64/stdio_.h
index 09b0172..afaeadc 100644
--- a/include/lib/libc/aarch64/stdio_.h
+++ b/include/lib/libc/aarch64/stdio_.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -7,11 +7,6 @@
 #ifndef STDIO__H
 #define STDIO__H
 
-#ifndef SIZET_
-typedef unsigned long size_t;
-#define SIZET_
-#endif
-
 #ifndef SSIZET_
 typedef long ssize_t;
 #define SSIZET_