C Bindings to the OpenSHMEM API

These are generated at runtime based on the users SHMEM_INSTALL_DIR environment variable.

Bundled OSSS-UCX Headers

For the purposes of building documentation, OSSS-UCX is included within the repository as a submodule. This is only used when building documentation within the docs.rs build tools. OSSS-UCX is not required for building applications--any OpenSHMEM 1.5 implementation will do.