I don't think a split is necessary. Nor do I think it would be viable for the C version. For the reasons jacob1 mentioned, I doubt anyone will want to maintain the C version in its current state. Some bits of it are just a horrible mess.
At the moment, the closest you'll get to a continuation of the C version is https://powdertoy.co.uk/Discussions/Thread/View.html?Thread=15340. That will gradually be converted to C++, and may turn out better, or worse, than the official C++ rewrite (TPT++).