diff --git a/include/rtdef.h b/include/rtdef.h
index 63038be5356..34bb283ae71 100644
--- a/include/rtdef.h
+++ b/include/rtdef.h
@@ -68,6 +68,8 @@
 #include "rtsched.h"
 #include "rttypes.h"
 
+#include "klibc/kerrno.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif