diff --git a/config.h.in b/config.h.in
index efe6cec6a..bd6c12c64 100644
--- a/config.h.in
+++ b/config.h.in
@@ -70,6 +70,9 @@
 #  define __svr4__
 #endif /* SVR4 */
 
+/* Define if you have realpath(3).  */
+#undef HAVE_REALPATH
+
 /* Define if you have getcwd(3).  */
 #undef HAVE_GETCWD