[clang] [clang-tools-extra] [Clang] Add support for the C `defer` TS (PR #162848)

[Corentin Jabot via cfe-commits]

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@@ -498,6 +498,11 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
   Builder.defineMacro("__STDC_EMBED_EMPTY__",
                       llvm::itostr(static_cast<int>(EmbedResult::Empty)));
 
+  // We define this to '1' here to indicate that we only support '_Defer'
+  // as a keyword; it will be set to '2' by <stddefer.h>.
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cor3ntin wrote:

There is a mismatch between these comment and your implementation of stddefer.h

https://github.com/llvm/llvm-project/pull/162848