message: guix: Appease travis.
diff: #!/usr/bin/env bash
  -export TZ=UTC
  export LC_ALL=C
  set -e -o pipefail
  +export TZ=UTC
  # Check that environment variables assumed to be set by the environment are set
  echo "Building for platform triple ${HOST:?not set} with reference timestamp ${SOURCE_DATE_EPOCH:?not set}..."
  