diff --git a/include/sys/cdefs.h b/include/sys/cdefs.h
index a60f0e2..f7c6a11 100644
--- a/include/sys/cdefs.h
+++ b/include/sys/cdefs.h
@@ -22,3 +22,7 @@
 # define __THROW
 # define __NTH(fct)     fct
 #endif
+
+#ifndef __RCSID
+#define __RCSID(x)
+#endif