The next release of C-Dogs SDL, version 0.6, is being delayed :(
An OS X bug with SDL image 1.2 means that it is unusable, as it creates corrupted images like this:
Which means the port to SDL 2 has to be moved ahead, delaying the next release.
SDL 2 will be quite a significant upgrade for C-Dogs, providing speed and input enhancements, so it will be worth the wait!