RFR: 8327049: Stop exporting debug.cpp functions on gcc

Thu Feb 29 13:28:15 UTC 2024

This is a partial backout of [JDK-8326509](https://bugs.openjdk.org/browse/JDK-8326509). It turned out that starting to export the functions from debug.cpp could have unintended consequences in certain circumstances, so revert back to the original situation where these functions were only exported on Windows.

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Commit messages:
 - 8327049: Stop exporting debug.cpp functions on gcc

Changes: https://git.openjdk.org/jdk/pull/18062/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18062&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327049
  Stats: 37 lines in 1 file changed: 7 ins; 0 del; 30 mod
  Patch: https://git.openjdk.org/jdk/pull/18062.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18062/head:pull/18062

PR: https://git.openjdk.org/jdk/pull/18062