[clang] [clang] Expose normalized module cache path in `HeaderSearch` (PR #185746)

[Cyndy Ishida via cfe-commits]

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@@ -1042,6 +1046,11 @@ void ApplyHeaderSearchOptions(HeaderSearch &HS,
 void normalizeModuleCachePath(FileManager &FileMgr, StringRef Path,
                               SmallVectorImpl<char> &NormalizedPath);
 
+std::string createSpecificModuleCachePath(FileManager &FileMgr,
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cyndyishida wrote:

>I'm not 100% sure these two calls do (or are supposed to) 
Can you add a FIXME in that case?

https://github.com/llvm/llvm-project/pull/185746