[devel] Mention zlib-libpng license in each source file
diff --git a/scripts/makefile.gcc b/scripts/makefile.gcc
index c4bfbf3..a7c4548 100644
--- a/scripts/makefile.gcc
+++ b/scripts/makefile.gcc
@@ -2,6 +2,8 @@
 # Copyright (C) 2008 Glenn Randers-Pehrson
 # Copyright (C) 2000 Cosmin Truta
 # Copyright (C) 1995 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
 
 # Location of the zlib library and include files