[clang] [clang][PAC] add support for options parameter to __ptrauth (PR #136828)

[Oliver Hunt via cfe-commits]

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@@ -65,6 +65,17 @@ enum class PointerAuthenticationMode : unsigned {
   SignAndAuth
 };
 
+static constexpr llvm::StringLiteral PointerAuthenticationOptionStrip = "strip";
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ojhunt wrote:

@cor3ntin @AaronBallman is there a better/more idiomatic way of doing these?

https://github.com/llvm/llvm-project/pull/136828