message: guix: Set ZERO_AR_DATE for darwin build determinism
  See comments inserted in this commit.
diff: @@ -148,6 +148,16 @@ export QT_RCC_TEST=1
  export QT_RCC_SOURCE_DATE_OVERRIDE=1
  export TAR_OPTIONS="--owner=0 --group=0 --numeric-owner --mtime='@${SOURCE_DATE_EPOCH}' --sort=name"
  export TZ="UTC"
  +case "$HOST" in
  + *darwin*)
  + # cctools AR, unlike GNU binutils AR, does not have a deterministic mode
  + # or a configure flag to enable determinism by default, it only
  + # understands if this env-var is set or not. See:
  + #
  + # https://github.com/tpoechtrager/cctools-port/blob/55562e4073dea0fbfd0b20e0bf69ffe6390c7f97/cctools/ar/archive.c#L334
  + export ZERO_AR_DATE=yes
  + ;;
  +esac
  ####################
  # Depends Building #
  