[devel] Revise references to zlib-libpng license
diff --git a/pngwio.c b/pngwio.c
index 0e7e8d0..c3a0996 100644
--- a/pngwio.c
+++ b/pngwio.c
@@ -7,7 +7,8 @@
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
* This code is released under the zlib-libpng license.
- * For conditions of distribution and use, see copyright notice in png.h
+ * For conditions of distribution and use, see copyright notice, disclaimer,
+ * and license in png.h
*
* This file provides a location for all output. Users who need
* special handling are expected to write functions that have the same