[llvm] Make WriteIndexesThinBackend multi threaded (PR #109847)

[Teresa Johnson via llvm-commits]

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@@ -1640,6 +1632,10 @@ class WriteIndexesThinBackend : public ThinBackendProc {
       MapVector<StringRef, BitcodeModule> &ModuleMap) override {
     StringRef ModulePath = BM.getModuleIdentifier();
 
+    // The contents of this file may be used as input to a native link, and must
+    // therefore contain the processed modules in a determinstic order than
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teresajohnson wrote:

s/than match/that matches/

https://github.com/llvm/llvm-project/pull/109847