diff --git a/src/config.in b/src/config.in
index 01195412f1d..adb95838dd4 100644
--- a/src/config.in
+++ b/src/config.in
@@ -168,6 +168,7 @@ Boston, MA 02111-1307, USA.  */
 #undef HAVE_STRING_H
 #undef STDC_HEADERS
 #undef TIME_WITH_SYS_TIME
+#undef HAVE_STDLIB_H
 
 #undef HAVE_LIBDNET
 #undef HAVE_LIBPTHREADS