Implement SPDX-Copyright

[Max Mehl <max.mehl@fsfe.org>]

Dear all,

Great to see such a big effort going on so smoothly thanks to the
excellent collaboration here! I would like to make a small suggestion
for further improvement while we are already touching so many files in
Linux.

Currently, the REUSE and SPDX team are discussing the official
introduction of the *SPDX-Copyright* tag [^1] [^2], perhaps for SPDX 2.2
and REUSE 3.0. 

The benefit is that tools can easily detect the correct line which holds
the copyright/author/year information. As of now, there are files which
contain multiple occurrences of the word "Copyright", "©" or "(c)",
which then requires the usage of error-prone logics and patterns.

Let me give a concrete example. The following header from one of the
first patches sent around here:


  // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   * Copyright (C) 2013 Pavel Machek <pavel@ucw.cz>
   * Copyright (C) 2013-2014 Aaro Koskinen <aaro.koskinen@iki.fi>


could become:


  // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   * SPDX-Copyright: (C) 2013 Pavel Machek <pavel@ucw.cz>
   * SPDX-Copyright: (C) 2013-2014 Aaro Koskinen <aaro.koskinen@iki.fi>


The usage of (C) or any other copyright symbols would probably be up to
personal style or legal requirements. All this tag intends to achieve is
to make automatic tooling more robust.

What do you think? Would someone see issues with realising this
technically rather simple change in the same course of action?

Best,
Max


[^1]: https://github.com/fsfe/reuse-docs/pull/23

[^2]: https://github.com/spdx/spdx-spec/issues/122

-- 
Max Mehl - Programme Manager - Free Software Foundation Europe
Contact and information: https://fsfe.org/about/mehl | @mxmehl
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