Merge topic 'misc-warnings'

6ed999674c Fix clang -Wdeprecated-pragma warnings by removing deprecated ATOMIC_VAR_INIT
162e017b2d Fix clang -Wstrict-prototypes by making main take void instead of nothing
b373a22991 Fix clang -Wreserved-identifier by renaming an enum

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Acked-by: scivision <michael@scivision.dev>
Merge-request: !8905