8375063: Update Libpng to 1.6.54

[mrserb]

Hi all,

This pull request contains a backport of commit a2e74957 from the openjdk/jdk repository.

The commit being backported was authored by Jayathirth D V on 21 Jan 2026 and was reviewed by Sergey Bylokhov and Phil Race.

Thanks!

---

Progress

• Change must not contain extraneous whitespace
• JDK-8375063 needs maintainer approval
• Commit message must refer to an issue

Issue

• JDK-8375063: Update Libpng to 1.6.54 (Bug - P3)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk21u-dev.git pull/2558/head:pull/2558
$ git checkout pull/2558

Update a local copy of the PR:
$ git checkout pull/2558
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/2558/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 2558

View PR using the GUI difftool:
$ git pr show -t 2558

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk21u-dev/pull/2558.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back serb! 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.

[openjdk]

⚠️ @mrserb 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.

[mlbridge]

Webrevs

• 00: Full (04ea224e)

[mrserb]

testing is in porgress