[clang] [llvm] [Clang][Darwin] Introduce `SubFrameworks` as a SDK default location (PR #115048)

[Cyndy Ishida via cfe-commits]

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@@ -346,6 +346,7 @@ void InitHeaderSearch::AddDefaultIncludePaths(
         AddPath("/System/DriverKit/System/Library/Frameworks", System, true);
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cyndyishida wrote:

I'd rather discuss DriverKit support separately, so I will merge this pr now. 
> Also, why's there an explicit /System/DriverKit here, didn't we generalize support for the system prefix?
I don't know, but it does not look generalized to me even downstream. perhaps a question for @yln ? 

https://github.com/llvm/llvm-project/pull/115048