diff --git a/zlib/ChangeLog.gcj b/zlib/ChangeLog.gcj
index 828f9c229d5..0278996b210 100644
--- a/zlib/ChangeLog.gcj
+++ b/zlib/ChangeLog.gcj
@@ -1,3 +1,7 @@
+2005-06-06  Rainer Orth  <ro@TechFak.Uni-Bielefeld.DE>
+
+	* zconf.h (NO_vsnprintf): Define on Tru64 UNIX V4.0.
+
 2005-05-09  Mike Stump  <mrs@apple.com>
 	
 	* configure: Regenerate.
diff --git a/zlib/zconf.h b/zlib/zconf.h
index 96dbc205c91..e63803b2d76 100644
--- a/zlib/zconf.h
+++ b/zlib/zconf.h
@@ -328,4 +328,12 @@ typedef uLong FAR uLongf;
 #endif
 #endif
 
+/* Tru64 UNIX V4.0 neither */
+#if defined(__alpha) && defined(__osf__)
+#include <unistd.h>
+#if _XOPEN_VERSION < 500
+#define NO_vsnprintf
+#endif
+#endif
+
 #endif /* ZCONF_H */