chore: import upstream snapshot with attribution

src/butil/debug/alias.h

@@ -0,0 +1,21 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BUTIL_DEBUG_ALIAS_H_
+#define BUTIL_DEBUG_ALIAS_H_
+
+#include "butil/base_export.h"
+
+namespace butil {
+namespace debug {
+
+// Make the optimizer think that var is aliased. This is to prevent it from
+// optimizing out variables that that would not otherwise be live at the point
+// of a potential crash.
+void BUTIL_EXPORT Alias(const void* var);
+
+}  // namespace debug
+}  // namespace butil
+
+#endif  // BUTIL_DEBUG_ALIAS_H_