C binding library interface for the Clue compiler

[Lyrth]

It would likely be beneficial to provide C bindings for the compiler so that it can be used in other non-Rust projects. This will allow Clue to be embedded without needing to call the Clue executable (via the CLI).

Source files for the binding and a C header file should be provided once this is implemented, and optionally, prebuilt dynamic libraries (aka. probably a cdylib on Rust) for each platform.

libtcc could be a (probably more complicated than needed) reference, but I personally like the structure. (Let us know of other implementations that can be a good reference for Clue's)