When the bssl-compat layer dynamically loads the OpenSSL libcrypto.so library, it should check its version to ensure it's compatible with the headers that bssl-compat was built against.

The OpenSSL release versioning policy states that "A minor release can, and generally will, introduce new features. However both the API and ABI will be preserved". Therefore, the major and minor version numbers must match.

The OPENSSL_VERSION_MAJOR & OPENSSL_VERSION_MINOR macros can be used at build time to capture the version of the headers that bssl-compat was compiled against.

The OPENSSL_version_major() & OPENSSL_version_minor() functions can be used at runtime to get the version of the dynamically loaded shared library.