diff --git a/zlib/gzio.c b/zlib/gzio.c
index 7e90f4928fc..ed4e77ca7e9 100644
--- a/zlib/gzio.c
+++ b/zlib/gzio.c
@@ -7,6 +7,11 @@
 
 /* @(#) $Id$ */
 
+/* Need to be included "early" to control other headers */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 #include <stdio.h>
 
 #include "zutil.h"