diff --git a/newlib/libc/include/sys/reent.h 
b/newlib/libc/include/sys/reent.h
index a6c923f1c..a02e7c2bd 100644
--- a/newlib/libc/include/sys/reent.h
+++ b/newlib/libc/include/sys/reent.h
@@ -12,6 +12,7 @@ extern "C" {

  #include <_ansi.h>
  #include <stddef.h>
+#include <sys/cdefs.h>
  #include <sys/_types.h>

  #define _NULL 0