[clang] [clang][driver][darwin] Prefer DarwinSDKInfo for platform identification and compatibility over the -isysroot path (PR #176541)

[Cyndy Ishida via cfe-commits]

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@@ -188,6 +188,11 @@ DarwinSDKInfo::parseDarwinSDKSettingsJSON(std::string FilePath,
   std::optional<StringRef> XcodePlatform = parseXcodePlatform(*Obj);
   std::pair<llvm::Triple::OSType, llvm::Triple::EnvironmentType>
       OSAndEnvironment = parseOSAndEnvironment(XcodePlatform);
+  // DisplayName should always be present, but don't die if it's missing for
+  // some weird reason.
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cyndyishida wrote:

nit: I find this comment is a bit too casual to burn in source. 
Maybe 

```
 // While `DisplayName` should always be present, allow fallbacks.
```


https://github.com/llvm/llvm-project/pull/176541