file(
  DOWNLOAD "${URL}" "${FILE}"
  STATUS status
  LOG log
)

list(GET status 0 status_code)
list(GET status 1 status_string)

if(NOT status_code EQUAL 0)
  message(FATAL_ERROR "error: downloading '${URL}' failed
  status_code: ${status_code}
  status_string: ${status_string}
  log: ${log}
")
endif()