Harder to do with C. Either you'll just add a small syntactical layer on top of C, mostly for cosmetic purposes (similar to python indentation tools for C or #define END } ), or you'll basically have a language that compiles to C (like p2c, f2c, Vala, SmartEiffel etc.).
Haven't seen a decent "transformation" of C that actually gets you more than it is worth, especially when it comes to interfacing to existing C libraries.
Edit: If you ever decide to make a Chess language, please make an IDE called Bangkok.