8341722: Fix some warnings as errors when building on Linux with toolchain clang

[MBaesken]

Backport of 8341722, changes of Lib.gmk are not in 23u so I omit those; otherwise applied clean.

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Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• JDK-8341722 needs maintainer approval
• Commit message must refer to an issue

Issue

• JDK-8341722: Fix some warnings as errors when building on Linux with toolchain clang (Bug - P4 - Requested)

Reviewers

• Christoph Langer (@RealCLanger - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk23u.git pull/213/head:pull/213
$ git checkout pull/213

Update a local copy of the PR:
$ git checkout pull/213
$ git pull https://git.openjdk.org/jdk23u.git pull/213/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 213

View PR using the GUI difftool:
$ git pr show -t 213

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk23u/pull/213.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back mbaesken! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 00: Full (c0e9fe3a)

[openjdk]

⚠️ @MBaesken This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[MBaesken]

Hi Christoph, thanks for the review !