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

[Aaron Ballman via cfe-commits]

================
@@ -803,17 +809,18 @@ class Qualifiers {
   static_assert(sizeof(PointerAuthQualifier) == sizeof(uint32_t),
                 "PointerAuthQualifier must be 32 bits");
 
+  static constexpr uint64_t PtrAuthShift = 32;
+  static constexpr uint64_t PtrAuthMask = uint64_t(0xffffffff) << PtrAuthShift;
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AaronBallman wrote:

```suggestion
  static constexpr uint64_t PtrAuthMask = 0xFFFFFFFFULL << PtrAuthShift;
```

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