RFR: 8351322: Parameterize link option for pthreads

Thu Mar 6 10:45:04 UTC 2025

Replace hardcoded instances of `-lpthread` with `$(LIBPTHREAD)`, so that it's possible to parameterize this for platforms that use different flags for enabling posix threads.

This work is a continuation of the work done by Greg Lewis in [1], but generalized for the full JDK, and set at the configure stage.

Sponsored by: The FreeBSD Foundation
Co-authored-by: Greg Lewis <glewis at eyesbeyond.com>

[1]: https://github.com/battleblow/jdk23u/commit/dbd90aa8ab0b7f5e4865864a7c63d975daacabf4

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Commit messages:
 - 8351322: Parameterize link option for pthreads

Changes: https://git.openjdk.org/jdk/pull/23930/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23930&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8351322
  Stats: 661 lines in 10 files changed: 9 ins; 0 del; 652 mod
  Patch: https://git.openjdk.org/jdk/pull/23930.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23930/head:pull/23930

PR: https://git.openjdk.org/jdk/pull/23930