Change the license from MIT to 0BSD

COPYING

@@ -1,21 +1,14 @@
-The MIT License (MIT)
-Copyright Contributors to the pythoncapi_compat project.
+BSD Zero Clause License
 
-Permission is hereby granted, free of charge, to any person obtaining a
-copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
+Copyright Contributors to the pythoncapi_compat project.
 
-The above copyright notice and this permission notice shall be included
-in all copies or substantial portions of the Software.
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted.
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.

README.rst

@@ -15,5 +15,6 @@ a wide range of Python versions with a single code base. It is made of the
 * `Documentation
   <https://pythoncapi-compat.readthedocs.io/en/latest/>`_
 
-This project is distributed under the MIT license and is covered by the `PSF
-Code of Conduct <https://www.python.org/psf/codeofconduct/>`_.
+This project is distributed under the `Zero Clause BSD (0BSD) license
+<https://opensource.org/licenses/0BSD>`_ and is covered by the `PSF Code of
+Conduct <https://www.python.org/psf/codeofconduct/>`_.

docs/changelog.rst

@@ -1,6 +1,10 @@
 Changelog
 =========
 
+* 2022-02-11: The project license changes from the MIT license to the Zero
+  Clause BSD (0BSD) license. Projects copying ``pythoncapi_compat.h`` no longer
+  have to include the MIT license and the copyright notice.
+* 2022-02-08: Add documentation.
 * 2022-02-09: ``pythoncapi_compat.h`` now supports C++ on Python 3.6 and newer:
   use ``nullptr`` and ``reinterpret_cast<type>`` cast on C++, and use ``NULL``
   and ``(type)`` cast on C.

docs/index.rst

@@ -23,5 +23,6 @@ Documentation:
    changelog
    links
 
-This project is distributed under the MIT license and is covered by the `PSF
-Code of Conduct <https://www.python.org/psf/codeofconduct/>`_.
+This project is distributed under the `Zero Clause BSD (0BSD) license
+<https://opensource.org/licenses/0BSD>`_ and is covered by the `PSF Code of
+Conduct <https://www.python.org/psf/codeofconduct/>`_.

docs/users.rst

@@ -60,11 +60,3 @@ Project with a strict contributor agreement:
 
 * `zodbpickle
   <https://github.com/zopefoundation/zodbpickle/pull/64>`_
-
-Discussion about the MIT license of the ``pythoncapi_compat.h`` file in the
-immutables project:
-
-* issue: `pythoncapi_compat.h is MIT licensed
-  <https://github.com/MagicStack/immutables/pull/64>`_
-* commit: `Clarify the license of the included pythoncapi_compat.h header
-  <https://github.com/MagicStack/immutables/commit/67c5edfb8284e39ab6a0be9a4644ede306c6e9bd>`_

pythoncapi_compat.h

@@ -1,7 +1,6 @@
-// Header file providing new functions of the Python C API to old Python
-// versions.
+// Header file providing new C API functions to old Python versions.
 //
-// File distributed under the MIT license.
+// File distributed under the Zero Clause BSD (0BSD) license.
 // Copyright Contributors to the pythoncapi_compat project.
 //
 // Homepage:
@@ -10,7 +9,7 @@
 // Latest version:
 // https://raw.githubusercontent.com/pythoncapi/pythoncapi_compat/master/pythoncapi_compat.h
 //
-// SPDX-License-Identifier: MIT
+// SPDX-License-Identifier: 0BSD
 
 #ifndef PYTHONCAPI_COMPAT
 #define PYTHONCAPI_COMPAT