the extensions from the given certificate request to the certificate.
Only RSA keys are currently supported.
+Note that this function will only set the @code{crq} if it is self
+signed and the signature is correct. See @code{gnutls_x509_crq_sign2()} .
+
@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS} (0) is returned, otherwise a
negative error value.
@end deftypefun