> libfive is 40K lines of mostly C++, and is extremely challenging to hack on, even as the original author. It's also frustrating to touch: if it's been a few months since I last compiled it, it's inevitable that the build will have broken, and I'll have to mess with CMake for 10 minutes to unbreak it.

I'm a bit shocked at this. Is build breakage that much of an issue? Is this "we are merging in patches and then fixing them up later"? Why would something not being touched break?