Merge topic 'duplicate-source-behavior' into release-3.31 3e15419bd4 target_sources: Restore toleration of duplicate CXX_MODULES sources 5cfb8ae790 Tests/CXXModules: add a test with duplicate sources Acked-by: Kitware Robot <kwrobot@kitware.com> Tested-by: buildbot <buildbot@kitware.com> Merge-request: !10155