[clang] [AArch64][FMV] Enable PAuth and BTI hardening of resolver functions (PR #141573)

[Alexandros Lamprineas via cfe-commits]

https://github.com/labrinea requested changes to this pull request.

We need this instead as I explained on the other thread.

```
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 2d37e0f13199..e26a540a8cb4 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4586,6 +4586,8 @@ void CodeGenModule::emitMultiVersionFunctions() {
         });
     CodeGenFunction CGF(*this);
     CGF.EmitMultiVersionResolver(ResolverFunc, Options);
+    SetFunctionAttributes(GD, ResolverFunc, /*IsIncompleteFunction=*/false,
+                          /*IsThunk=*/false);
   }

   // Ensure that any additions to the deferred decls list caused by emitting a
```

https://github.com/llvm/llvm-project/pull/141573