Note the dodgy _CONFIG_H_ check can be removed when >=llvm-libunwind-15
(which adds _VERSION) is well established: https://reviews.llvm.org/D121015
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -1359,3 +1359,3 @@
 
-#ifdef __APPLE__
+#if defined(__APPLE__) || defined(_LIBUNWIND_VERSION) || defined(____LIBUNWIND_CONFIG_H__)
     rc = unw_getcontext( &unw_context );