there is a libc++!! first result in google, for llvm..

again, when you compile code in libc* it compiles against these libraries

these libraries are essential to an open source operating system that are posix compatible, so if you get these working on your operating system you can easily start compiling code

again, if youre into foresensics or security, you should deeply review this code, especially if developing software or an operating system on your own

basically, these libraries interface with the operating system and the kernel which interfaces with the kernel, and you could get a signficant boost in performance if you modify these files to your liking, but id suggest a good phd if youre looking to help the unix stratosphere