--- zlib-1.2.3/zlib.h.orig	2006-02-18 08:37:38.000000000 +0000
+++ zlib-1.2.3/zlib.h	2006-02-18 08:40:28.000000000 +0000
@@ -1240,6 +1240,9 @@
    error occurred in the file system and not in the compression library,
    errnum is set to Z_ERRNO and the application may consult errno
    to get the exact error code.
+
+   The application must not modify the returned string and future calls to
+   this function may invalidate the returned string.
 */
 
 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
