[clang] [FMV][AIX] Implement target_clones (PR #177428)

[Zarko Todorovski via cfe-commits]

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@@ -2092,6 +2092,20 @@ static bool isUniqueInternalLinkageDecl(GlobalDecl GD,
          (CGM.getFunctionLinkage(GD) == llvm::GlobalValue::InternalLinkage);
 }
 
+// On certain platforms, a declared (but not defined) FMV shall be treated
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ZarkoT wrote:

Seems like this is AIX only? Maybe adjust the comment in that case. 

https://github.com/llvm/llvm-project/pull/177428