Index: zlib.h
===================================================================
--- zlib.h.orig	2005-07-18 04:26:49.000000000 +0200
+++ zlib.h	2009-11-24 17:22:26.357480000 +0100
@@ -1119,7 +1119,12 @@ ZEXTERN int ZEXPORT    gzwrite OF((gzFil
    (0 in case of error).
 */
 
-ZEXTERN int ZEXPORTVA   gzprintf OF((gzFile file, const char *format, ...));
+
+ZEXTERN int ZEXPORTVA   gzprintf OF((gzFile file, const char *format, ...)) 
+#ifdef __GNUC__
+	__attribute__((__format__(__printf__,2,3)))
+#endif
+;
 /*
      Converts, formats, and writes the args to the compressed file under
    control of the format string, as in fprintf. gzprintf returns the number of