Hmm. I don't really see the point of this at all. Upgrading SharedCLibrary might be a hassle, but you only have to do it once. Going to all this trouble just so people can keep their old C libraries (with their old bugs) seems an awful waste of effort.
In any case, if it supports any version of SharedCLibrary, it's not going to have any of the new C99 functions in it is it (unless I've missed something obvious), so bang goes support for long long ints and all the useful new library functions. What's the use of that?