Merge topic 'warnings-cleanup'

7e4e192ce2 Source: fix clang-tidy modernize-redundant-void-arg warning
8d671dd94c Source: fix more -Wmissing-prototypes warnings
1cf14f8c03 Source: fix many -Wmissing-prototypes warnings by marking functions static
319944b3d2 Source: fix some -Wunused-macros warnings
5257d9e71a Source: fix only -Wshorten-64-to-32 warning with explicit cast

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !6648