Fix CI build warnings

[wgtmac]

There are a lot of CI warnings that are worth fixing. For example: https://github.com/apache/iceberg-cpp/actions/runs/19386197700/job/55473420291?pr=320

[Jinchul81]

I am interested in this work as a newcomer. May I provide a PR?

[Fokko]

@Jinchul81 Go ahead, first come, first serve :)

[Jinchul81]

Please review the PR #328