[lld] [llvm] [lld][MachO] Follow-up to use madvise() for threaded file page-in. (PR #157917)

[Ellis Hoag via llvm-commits]

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@@ -292,12 +297,13 @@ struct DeferredFile {
 using DeferredFiles = std::vector<DeferredFile>;
 
 #if LLVM_ENABLE_THREADS
-class SerialBackgroundQueue {
+class SerialBackgroundWorkQueue {
   std::deque<std::function<void()>> queue;
   std::thread *running;
   std::mutex mutex;
 
 public:
+  bool stopAllWork = false;
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ellishg wrote:

```suggestion
  std::atomic_bool stopAllWork = false;
```

I think we need to use atomics to make sure the compiler doesn't optimize away the check

https://github.com/llvm/llvm-project/pull/157917