Merge topic 'rpath-unrecognized-format' into release-3.22

643fc46bdc file(RPATH): Restore tolerance of unknown formats if new RPATH is empty
5596cba7dc cmSystemTools: Remove unnecessary mark-as-used casts to void

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !6779