[jdk17u-dev] RFR: 8289910: unify os::message_box across posix platforms

[Matthias Baesken]

8289910: unify os::message_box across posix platforms

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Commit messages:
 - Backport e5491a2605177a9dca87a060d99aa5ea4fd4a239

Changes: https://git.openjdk.org/jdk17u-dev/pull/629/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=629&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8289910
  Stats: 77 lines in 4 files changed: 20 ins; 57 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/629.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/629/head:pull/629

PR: https://git.openjdk.org/jdk17u-dev/pull/629