[devel] Mention zlib-libpng license in each source file
diff --git a/pngset.c b/pngset.c
index f3c66c0..071b026 100644
--- a/pngset.c
+++ b/pngset.c
@@ -2,11 +2,13 @@
/* pngset.c - storage of image information into info struct
*
* Last changed in libpng 1.4.0 [June 24, 2009]
- * For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1998-2009 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (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
+ *
* The functions here are used during reads to store data from the file
* into the info struct, and during writes to store application data
* into the info struct for writing into the file. This abstracts the