See also: https://github.com/keiichiw/constexpr-8cc
This tool embeds a C compiler as a constexpr, so in theory you can do all the work at compile time and just output a static string at run time. But currently I am having trouble getting it to work, so it's perhaps not so glorious other than the amount of time it takes to compile.
ELVM [0] also has a C++14 constexpr target, also using 8cc as the frontend !