Well, if it's written in C, it can be used pretty much anywhere and linked to from pretty much anything. Yes, the code needs to be written portably, but that's

Well, if it's written in C, it can be used pretty much anywhere and linked to from pretty much anything. Yes, the code needs to be written portably, but that's a solved problem. In addition to that, the FSF has some weird religious adherence to C that goes beyond linkability. e.g. they're opposed to libraries being written in highly portable C++ which export their bindings in pure C, even if you only used features supported by Cfront in 1990.