[clang] [clang][AIX] Handle triple environment component for per target runtime directory (PR #140850)

[Daniel Chen via cfe-commits]

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@@ -935,6 +935,14 @@ ToolChain::getTargetSubDirPath(StringRef BaseDir) const {
   if (auto Path = getPathForTriple(T))
     return *Path;
 
+  // On AIX, the environment component is not used in the target sub dir name.
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DanielCChen wrote:

After re-exam the code, I think we can move the code I linked from `getRuntimePath` to `getTargetSubDirPath`. 
It will probably be OK to add a check of `T.isOSAIX()` in the same block of `T.isOSzOS` so `getTripleWithoutOSVersion` can be re-used.

https://github.com/llvm/llvm-project/pull/140850