[clang] [Clang] Produce deterministic hash for anonymous namespaces. (PR #194542)

[Corentin Jabot via cfe-commits]

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@@ -636,6 +636,8 @@ Windows Support
 
 - Clang now defines the ``_MSVC_TRADITIONAL`` macro as ``1`` when emulating MSVC
   19.15 (Visual Studio 2017 version 15.8) and later. (#GH47114)
+- ``-fmacro-prefix-map=`` (``-ffile-prefix-map=``) now affects an anonymous namespace hash generation
+  for the MSVC targets and allows deterministic symbol mangling for reproducible builds. (#GH194542)
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cor3ntin wrote:

```suggestion
- ``-fmacro-prefix-map=`` (``-ffile-prefix-map=``) now affects an anonymous namespace hash generation
  for the MSVC targets and allows deterministic symbol mangling for reproducible builds.
```

https://github.com/llvm/llvm-project/pull/194542