in order to make builds reproducible. See https://reproducible-builds.org/ for why this is good and https://reproducible-builds.org/specs/source-date-epoch/ for the definition of this variable. Signed-off-by: Bernhard M. Wiedemann <bwiedemann@suse.de> Upstream-commit: 760763e9957840f1983a5006f4e66d6920ec496e Component: engine