0631a46a94
In fully self-contained deployments it may be desirable to build iPXE with an empty CROSSCERT source to avoid talking to external services. Add an explicit check for this case and make validator_start_download fail immediately if the base URI is empty. Signed-off-by: Ladi Prosek <lprosek@redhat.com> Modified-by: Michael Brown <mcb30@ipxe.org> Signed-off-by: Michael Brown <mcb30@ipxe.org>