As far as I know, C2 is designed for exporting Javascript only. Also all plugins/behaviors are written in Javascript. Javascript is a highly dynamic language, means that for example a variable can take a number or a string at runtime. This isn't possible in language like C or C++. In this languages a variable is bound at compile time to a distinct type like string, float, integer ....
So it's very hard to translate Javascript to C or C++ , the other way around is possible.
So if you want other exporters you have to rewrite Construct.