It seems like a pretty specific question where any answer containing a general purpose language that doesn't support C would qualify. Or is it that there is the possibility of more than one correct answer that makes it disqualified for asking on StackExchange?
Responses to comments:
@t-sar: I want to know the answer to my question as I am building large projects in C and want to say definitively "by writing in C this library can be called by any maintained general purpose programming-language".
Link to my question: https://softwareengineering.stackexchange.com/q/444976