This is KnightOS's shared C library. Note that it is not compliant with any particular standard and doesn't even slightly resemble POSIX. That being said, where POSIX and KnightOS have similar functions, our libc does implement some of the things you'd find in a POSIX-compliant OS.
First, install the KnightOS SDK.
$ knightos init
$ make
Use make package
to get a package that you can install.
This project follows the same standards for contribution as the rest of the KnightOS userspace. These standards are documented at KnightOS/KnightOS on GitHub.