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

[Mariya Podchishchaeva via cfe-commits]

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+// RUN: %clang_cc1 -verify -triple x86_64-unknown-linux-gnu -fsyntax-only --embed-dir=%S/Inputs -std=c23 %s -pedantic -Wpre-c23-compat
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Fznamznon wrote:

Done.

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