The header "config.h" needs to be included "early" to control other headers.

This time the inclusion of <stdio.h> before "config.h" enabled legacy large
file support, seek64() and similar, on AIX breaking the compile of "gzio.c"

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"