cleanup()
public
It is only necessary to run cleanup when engines are loaded via
OpenSSL::Engine.load. However, running cleanup before exit is
recommended.
See also, www.openssl.org/docs/crypto/engine.html
static VALUE
ossl_engine_s_cleanup(VALUE self)
{
#if defined(HAVE_ENGINE_CLEANUP)
ENGINE_cleanup();
#endif
return Qnil;
}