Ok, I just checked into GIT a fix to allow the due_can library to work with stock 1.5.2. So, you don't need to check out the Arduino code from git to use it anymore.
Heres the link again: git://github.com/collin80/due_can.git
If you don't want to use git you can just download the zip of the master at this link: https://github.com/collin80/due_can/archive/master.zip