cleanup()
public
It is only necessary to run cleanup when engines are loaded via
OpenSSL::Engine.load. However, running cleanup before exit is
recommended.
Note that this is needed and works only in OpenSSL < 1.1.0.
static VALUE
ossl_engine_s_cleanup(VALUE self)
{
#if defined(LIBRESSL_VERSION_NUMBER) || OPENSSL_VERSION_NUMBER < 0x10100000
ENGINE_cleanup();
#endif
return Qnil;
}