[clang] [PAC] Add support for __ptrauth type qualifier (PR #100830)

[Aaron Ballman via cfe-commits]

================
@@ -980,6 +980,25 @@ def err_ptrauth_indirect_goto_addrlabel_arithmetic : Error<
   "%select{subtraction|addition}0 of address-of-label expressions is not "
   "supported with ptrauth indirect gotos">;
 
+// __ptrauth qualifier
+def err_ptrauth_qualifier_invalid : Error<
+  "%select{return types|parameter types|properties}1 may not be qualified with __ptrauth; type is %0">;
+def err_ptrauth_qualifier_cast : Error<
+  "cast types may not be qualified with __ptrauth; type is %0">;
----------------
AaronBallman wrote:

```suggestion
  "cannot cast to '__ptrauth'-qualified type %0">;
```

https://github.com/llvm/llvm-project/pull/100830