[clang] [clang][C23] Support N3029 Improved Normal Enumerations (PR #103917)

[Aaron Ballman via cfe-commits]

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@@ -169,13 +169,19 @@ enum class GH42372_2 {
   One
 };
 
+enum IncOverflow {
+  V2 = __INT_MAX__,
+  V3 // c99-warning {{incremented enumerator value that is exceeding range of 'int' is a C23 extension}}
+#if __STDC_VERSION__ >= 202311L
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AaronBallman wrote:

You can give the C23 RUN line its own `-verify` prefix rather than using `#if`

https://github.com/llvm/llvm-project/pull/103917