[committed] libstdc++: Fix copyright notice to use usual form [PR108413]

[Jonathan Wakely]

Pushed to trunk. Backport to gcc-12 for follow (for the first two parts
of the change, tzdb.cc isn't on the branch).

-- >8 --

libstdc++-v3/ChangeLog:

	PR libstdc++/108413
	* include/c_compatibility/stdatomic.h: Change copyright line to
	be consistent with other headers contributed under DCO terms.
	* include/std/expected: Add full stop to copyright line.
	* src/c++20/tzdb.cc: Likewise.
---
 libstdc++-v3/include/c_compatibility/stdatomic.h | 2 +-
 libstdc++-v3/include/std/expected                | 2 +-
 libstdc++-v3/src/c++20/tzdb.cc                   | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/include/c_compatibility/stdatomic.h b/libstdc++-v3/include/c_compatibility/stdatomic.h
index a51a84c2054..b565a1c1ab1 100644
--- a/libstdc++-v3/include/c_compatibility/stdatomic.h
+++ b/libstdc++-v3/include/c_compatibility/stdatomic.h
@@ -1,6 +1,6 @@
 // C compatibility header <stdatomic.h> -*- C++ -*-
 
-// Copyright (C) 2022 The GCC developers
+// Copyright The GNU Toolchain Authors.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
diff --git a/libstdc++-v3/include/std/expected b/libstdc++-v3/include/std/expected
index 555779581f2..9a52e2574bf 100644
--- a/libstdc++-v3/include/std/expected
+++ b/libstdc++-v3/include/std/expected
@@ -1,6 +1,6 @@
 // <expected> -*- C++ -*-
 
-// Copyright The GNU Toolchain Authors
+// Copyright The GNU Toolchain Authors.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
diff --git a/libstdc++-v3/src/c++20/tzdb.cc b/libstdc++-v3/src/c++20/tzdb.cc
index eaaea367f4f..2ce53d38768 100644
--- a/libstdc++-v3/src/c++20/tzdb.cc
+++ b/libstdc++-v3/src/c++20/tzdb.cc
@@ -1,6 +1,6 @@
 // chrono::tzdb -*- C++ -*-
 
-// Copyright The GNU Toolchain Authors
+// Copyright The GNU Toolchain Authors.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
-- 
2.39.0