Update libpng to version 1.6.3

Change-Id: I86cb46ec376eb41324b82d2875757aeda734c5c1
diff --git a/scripts/symbols.dfn b/scripts/symbols.dfn
new file mode 100644
index 0000000..6f52918
--- /dev/null
+++ b/scripts/symbols.dfn
@@ -0,0 +1,58 @@
+
+/* symbols.dfn - find all exported symbols
+ *
+ * Last changed in libpng version 1.5.0 [January 6, 2011]
+ * Copyright (c) 1998-2011 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
+ */
+
+/* NOTE: making 'symbols.chk' checks both that the exported
+ * symbols in the library don't change and (implicitly) that
+ * scripts/pnglibconf.h.prebuilt is as expected.  If scripts/pnglibconf.h.prebuilt
+ * is remade using scripts/pnglibconf.dfa then this checks the
+ * .dfa file too.
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+        PNG_DFN "@" name "@ @@" ordinal "@"
+#define PNG_REMOVED(ordinal, type, name, args, attributes)\
+        PNG_DFN "; @" name "@ @@" ordinal "@"
+#define PNG_EXPORT_LAST_ORDINAL(ordinal)\
+        PNG_DFN "; @@" ordinal "@"
+
+/* Read the defaults, but use scripts/pnglibconf.h.prebuilt; the 'standard'
+ * header file.
+ */
+#include "pnglibconf.h.prebuilt"
+#include "../png.h"
+
+/* Some things are turned off by default.  Turn these things
+ * on here (by hand) to get the APIs they expose and validate
+ * that no harm is done.  This list is the set of options
+ * defaulted to 'off' in scripts/pnglibconf.dfa
+ *
+ * Maintenance: if scripts/pnglibconf.dfa options are changed
+ * from, or to, 'disabled' this needs updating!
+ */
+#define PNG_BENIGN_ERRORS_SUPPORTED
+#define PNG_ERROR_NUMBERS_SUPPORTED
+#define PNG_READ_BIG_ENDIAN_SUPPORTED  /* should do nothing! */
+#define PNG_INCH_CONVERSIONS_SUPPORTED
+#define PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+#define PNG_SET_OPTION_SUPPORTED
+
+#undef PNG_H
+#include "../png.h"
+
+/* Finally there are a couple of places where option support
+ * actually changes the APIs revealed using a #if/#else/#endif
+ * test in png.h, test these here.
+ */
+#undef  PNG_FLOATING_POINT_SUPPORTED /* Exposes 'fixed' APIs */
+#undef  PNG_ERROR_TEXT_SUPPORTED     /* Exposes unsupported APIs */
+
+#undef PNG_H
+#include "../png.h"