+#elif defined(USE_GNUTLS)
+
+#include <gnutls/gnutls.h>
+
+#define SSLI_ERROR_WANT_READ GNUTLS_E_AGAIN
+#define SSLI_ERROR_WANT_WRITE GNUTLS_E_AGAIN
+#define SSLI_ERROR_ZERO_RETURN GNUTLS_E_PREMATURE_TERMINATION
+#define SSLI_ERROR_CONNRESET GNUTLS_E_PREMATURE_TERMINATION
+#define SSLI_ERROR_SYSCALL GNUTLS_E_PREMATURE_TERMINATION
+
+typedef gnutls_session_t SSL_handle_t;
+
+#else /* OpenSSL */
+#include <openssl/x509v3.h>
+#include <openssl/ssl.h>