[clang-tools-extra] Add new tool: clang-read-diagnostics (PR #118522)

[Jon Roelofs via cfe-commits]

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@@ -0,0 +1,129 @@
+//===---- ClangReadDiagnostics.cpp - clang-read-diagnostics tool ----------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This tool is for reading clang diagnostics files from -serialize-diagnostics.
+//
+// Example usage:
+//
+// $ clang -serialize-diagnostics foo.c.diag foo.c
+// $ clang-read-diagnostics foo.c.diag
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jroelofs wrote:

This deserves to be a test, too.

https://github.com/llvm/llvm-project/pull/118522