A really interesting project. It looks like their SVN/bug tracker are using outdated SSL certificates, and even if you bypass those it will only give you an access denied error. However you can download the source tarballs, so I made a unofficial mirror of the code on GitHub (since I couldn’t find any of those as well).
My first thought when I saw the project was, “well this would be cool for an experimental kernel,” however they list that one of the two things this isn’t for is “Low-level, self-standing programs such as OS kernels.” Though I wonder if a Rust-style (in that similar to Redox and presumably other Rust kernels) microkernel would be possible, with an “unsafe” microkernel and the the modules being built off of the “unsafe” kernel with the FailSafeC compiler. I’m not familiar with the design of the compiler though, and it does appear to have some sort of runtime which would complicate porting it, but it would definitely be an interesting/fun project.
Presumably you could use this compiler as a test suite, and generate production binaries with gcc/clang.