If I had to guess why there are no such lightweight library, it is because when somehow the library API doesn't provide what you want, you cannot hack the library itself easily. If you import the source code you may have trouble building it, and maintening such "patch" is not a lot of fun.
Yes. I guess the fact C doesn't have advanced features like generics and templates probably have made the problem worse, making it difficult to create a "drop-in" API.
