Add column: C interoperability

[d9k]

Example possible captions: "No" / "manual" / "autogeneration".
May be a link to github issue or documentation on topic.

[forksnd]

Another thing to consider is whether the language allows you to inject arbitrary C code in the generated code (for quick optimisation, dealing with headers, etc). Nim and Haxe seem to do that, ECL does it but apparently only in top-level, etc.