[libunwind] [libunwind] Add GCS support for AArch64 (PR #99335)

[Fangrui Song via cfe-commits]

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@@ -170,6 +183,10 @@ unwind_phase1(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *except
 }
 extern int __unw_step_stage2(unw_cursor_t *);
 
+#if defined(_LIBUNWIND_USE_GCS)
+// Enable the GCS target feature to permit GCS instructions to be used.
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MaskRay wrote:

Might be useful to elaborate what instructions need to use the GCS version.

https://github.com/llvm/llvm-project/pull/99335