RFR: 8353580: libjpeg is not found if not installed in system directories

[snake66]

The autoconf scrips fail to find libjpeg on systems where it's not installed in the default system include and library directories. It should check for the pkgconfig in these cases.

This work is sponsored by The FreeBSD Foundation

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Commit messages:
 - JDK-8353580: libjpeg is not found if not installed in system directories

Changes: https://git.openjdk.org/jdk/pull/24403/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24403&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353580
  Stats: 17 lines in 2 files changed: 11 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/24403.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24403/head:pull/24403

PR: https://git.openjdk.org/jdk/pull/24403