[devel] Mention zlib-libpng license in each source file
diff --git a/scripts/makefile.linux b/scripts/makefile.linux
index 06a7103..e2f8ad5 100644
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -2,6 +2,8 @@
 # Copyright (C) 1998, 1999, 2002, 2006, 2008 Greg Roelofs and
 # Glenn Randers-Pehrson
 # Copyright (C) 1996, 1997 Andreas Dilger
+#
+# This code is released under the zlib-libpng license.
 # For conditions of distribution and use, see copyright notice in png.h
 
 # Library name: