diff --git a/appl/xnlock/xnlock.c b/appl/xnlock/xnlock.c
index d880e9f60..1717edade 100644
--- a/appl/xnlock/xnlock.c
+++ b/appl/xnlock/xnlock.c
@@ -19,9 +19,6 @@ RCSID("$Id$");
 #include <X11/Intrinsic.h>
 #include <X11/keysym.h>
 #include <X11/Shell.h>
-#ifdef strerror
-#undef strerror
-#endif
 #include <ctype.h>
 #ifdef HAVE_SYS_TYPES_H
 #include <sys/types.h>