[clang] [clang][modules][deps] Add mutex as an alternative to file lock (PR #129751)

[Michael Spencer via cfe-commits]

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@@ -95,6 +96,10 @@ class DependencyScanningService {
     return SharedCache;
   }
 
+  ModuleCacheMutexes &getSharedModuleCacheMutexes() {
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Bigcheese wrote:

I don't think we need shared_ptr here, the lifetime of workers is already bound to the service.

https://github.com/llvm/llvm-project/pull/129751