Add libpng 1.6.6.

libs/lpng166/scripts/intprefix.dfn

@@ -0,0 +1,19 @@
+
+/* intprefix.dfn - generate an unprefixed internal symbol list
+ *
+ * Last changed in libpng version 1.6.0 [January 30, 2012]
+ * Copyright (c) 2012 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_INTERNAL_DATA(type, name, array)\
+        PNG_DFN "@" name "@"
+
+#define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
+        PNG_DFN "@" name "@"
+
+#define PNGPREFIX_H /* self generation */
+#include "../pngpriv.h"