- Leave fd 3 open for GnuTLS < 3.3.10 that don't have https://gitlab.com/gnutls/gnutls/commit/684b825f5f78cc7ad1f61be232fd20ee0bc5b56f

  "  When gnutls_global_init() is called manually from the application check the urandom fd for validity
     That addresses the issue where a server closes all open file descriptors
     and then calls gnutls_global_init().  "