ZOSLIB is a z/OS C/C++ library, available in https://github.com/ibmruntimes/zoslib. It is an extended implementation of the z/OS LE C Runtime Library.
Just add zoslib as a dependency and zoslib and it will automatically be statically linked to your application.
For example:
ZOPEN_TARBALL_DEPS="make gzip tar zoslib"