RFR: 8284752: Zero does not build on Mac OS X due to missing os::current_thread_enable_wx implementation

[Johannes Bechberger]

Adds an implementation of the missing method (guarded with `defined(AARCH64) && defined(__APPLE__)`) and fixes the compilation issues on Mac M1.

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Commit messages:
 - Add os::current_thread_enable_wx implementation to bsd_zero

Changes: https://git.openjdk.java.net/jdk/pull/8200/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8200&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284752
  Stats: 6 lines in 1 file changed: 6 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8200.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8200/head:pull/8200

PR: https://git.openjdk.java.net/jdk/pull/8200