The old method only worked out of the box if you were running Python
2.1 on a 586. I imagine that is too small a slice of current users to
be worth hard coding ;).
This catches the Python demos up to:
commit 003b9ec501
Author: Ian Abbott <abbotti@mev.co.uk>
Date: Mon Nov 8 11:01:42 2010 +0000
Add chanlist_len parameter to comedi_get_cmd_generic_timed.