Update libpng to latest 1.6.56 version, we use libpng in splashscreen implementation.
Testing is green with this libpng update. We are seeing windows build failure because of https://github.com/pnggroup/libpng/commit/9929ba276ea3f7b4f03fdc0c693997ece3609c5b, where "warning C4146: unary minus operator applied to unsigned type, result still unsigned" is treated as error. We are disabling this warning in pngread.c as part of this libpng update. ------------- Commit messages: - Update copyright year - Disable warning for pngread.c file only - libpng update Changes: https://git.openjdk.org/jdk/pull/30489/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=30489&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8380959 Stats: 259 lines in 15 files changed: 137 ins; 41 del; 81 mod Patch: https://git.openjdk.org/jdk/pull/30489.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/30489/head:pull/30489 PR: https://git.openjdk.org/jdk/pull/30489
