Allow to override build date with SOURCE_DATE_EPOCH

[bmwiedemann]

Description:

• Allow to override build date with SOURCE_DATE_EPOCH
  in order to make builds reproducible.

This PR was done while working on reproducible builds for openSUSE.

Rationale:

• 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.
• Without this patch, .xml files varied for each build in

    <oval:timestamp>2021-02-22T21:05:22</oval:timestamp>

[openscap-ci]

Can one of the admins verify this patch?

[openscap-ci]

Can one of the admins verify this patch?

[openshift-ci-robot]

Hi @bmwiedemann. Thanks for your PR.

I'm waiting for a ComplianceAsCode member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[ggbecker]

@openscap-ci ok to test

[openscap-ci]

Changes identified:
Others:
 Changes in Python files.

Show details

Others:
 Python abstract syntax tree change found in ssg/constants.py.

Recommended tests to execute:
 (cd build && cmake ../ && ctest -j4)

[jan-cerny]

/ok-to-test

[ggbecker]

LGTM. I'm going to add documentation about this on a subsequential PR.