I think the problem is that C is simply ill-suited for these "high level" constructs. The best you're likely to get is an ad-hoc special library like for wchar_t and wcslen and friends. Do we really want that?

I'd argue that linked list might make a better candidate for inclusions, because I've seen the kernel's list.h or similar implementations in many projects and that's stuff is trickier to get right than stuffing a pointer and a size_t in a struct.