[clang] [clang][PAC][darwin] Set correct default ptrauth features for arm64e-darwin (PR #153722)

[Oliver Hunt via cfe-commits]

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@@ -3291,6 +3291,39 @@ void Darwin::addClangTargetOptions(
     if (!RequiresSubdirectorySearch)
       CC1Args.push_back("-fno-modulemap-allow-subdirectory-search");
   }
+
+  if (getTriple().isArm64e()) {
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ojhunt wrote:

I've done this - the out of date-ness was not bad, it was just lacking the new features that this PR was adding - but I've moved it to there as well.

I was concerned about pushing it down to MachO before, but I've realized that there is unlikely to be another platform built on MachOs targeting arm64e specifically :D

https://github.com/llvm/llvm-project/pull/153722