Errors where:

/buildbot/amd64-ubuntu-2004-msan/build/sql/item.h:6478:12: error: 'val_datetime_packed' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
  longlong val_datetime_packed(THD *thd)
           ^
/buildbot/amd64-ubuntu-2004-msan/build/sql/item.h:3501:12: note: overridden virtual function is here
  longlong val_datetime_packed(THD *thd) override;
           ^
/buildbot/amd64-ubuntu-2004-msan/build/sql/item.h:6480:12: error: 'val_time_packed' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
  longlong val_time_packed(THD *thd)
           ^
/buildbot/amd64-ubuntu-2004-msan/build/sql/item.h:3502:12: note: overridden virtual function is here
  longlong val_time_packed(THD *thd) override;
           ^