diff --git a/rtemsbsd/include/rtems/bsd/sys/errno.h b/rtemsbsd/include/rtems/bsd/sys/errno.h
index 2ed71acc..7fad3cf0 100644
--- a/rtemsbsd/include/rtems/bsd/sys/errno.h
+++ b/rtemsbsd/include/rtems/bsd/sys/errno.h
@@ -40,10 +40,12 @@
 
 #ifndef _KERNEL
 #include <sys/cdefs.h>
+#ifndef __rtems__
 __BEGIN_DECLS
 int *	__error(void);
 __END_DECLS
 #define	errno		(* __error())
+#endif /* __rtems__ */
 #endif
 
 #ifndef __rtems__