Make png2c.py work with Python 3.9+

array.tostring() was removed in 3.9, so use tobytes() instead.

This makes the script incompatible with Python 2, but this shouldn't be
much of a concern any more these days.

misc/scripts/png2c.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 
 # This script is a slightly modified version of the original found at
 #
@@ -50,7 +50,7 @@ for path in sys.argv[1:]:
         # Each PNG file starts with a 8 byte signature that should be followed
         # by IHDR chunk which is always 13 bytes in length so the first 16
         # bytes are fixed (or at least we expect them to be).
-        if bytes[0:16].tostring() != b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR':
+        if bytes[0:16].tobytes() != b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR':
                 print('"%s" doesn\'t seem to be a valid PNG file.' % filename)
                 continue