* tests: New test for ctypes buffers (pybind#2502)

* fix: fix buffer_info segfault on views with no stride (pybind11#2502)

* Explicit conversions in buffer_info to make clang happy (pybind#2502)

* Another explicit cast in buffer_info constructor for clang (pybind#2502)

* Simpler implementation of buffer_info constructor from Py_buffer.

* Move test_ctypes_buffer into test_buffers

* Comment on why view->strides may be NULL (and fix some whitespace)

* Use c_strides() instead of zero when view->strides is NULL.

c_strides and f_strides are moved from numpy.h (py::array)
to buffer_info.h (py::detail) so they can be used from the
buffer_info Py_buffer constructor.

* Increase ctypes buffer test coverage in test_buffers.

* Split ctypes tests and skip one which is broken in PyPy2.

* WIP: module -> module_ without typedef

* refactor: allow py::module to work again

* feat: import check as a common function

* docs: add cmake to docs

Co-authored-by: Hyrum Wright <hwright@google.com>

* Allow function/functor passed to py::vectorize to return void

* Stealing @sizmailov's test and fixing unused argument warning

* Add missing std::move()

RVO doesn't work here because function return type is different from
actual returned type

* remove extra EOL

* docs: add a few details

* chore: pre-commit autoupdate

* Remove array_iterator, array_begin, and array_end (in detail namespace)

Co-authored-by: Sergei Izmailov <sergei.a.izmailov@gmail.com>
Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>

Add unchecked_reference::operator() and operator[] to overload resolution of unchecked_mutable_reference (#2514)

* Add tests demonstrating the problem with deregistering pybind11 instances

* Fix deregistering of different pybind11 instance from internals

Co-authored-by: Yannick Jadoul <yannick.jadoul@belgacom.net>
Co-authored-by: Blistic <wots_wot@hotmail.com>

Unify Python 2 & 3 py::module constructor, and make contructor with pre-allocated PyModuleDef private (#2534)

Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>

Moving tp_class access, and consistent fully-qualified naming for PyPy, to detail::get_tp_name (#2520)

* Moving tp_class access, and consistent fully-qualified naming for PyPy, to detail::get_tp_name

* Change get_tp_name to get_fully_qualified_tp_name

On very incomplete python installations (e.g. within Docker), it's
possible that distutils is not installed. In that case, the
``execute_command`` statement that queries distutils for the Python
module extension fails, and pybind11 uses the empty string. This commit
adds an extra check that causes a CMake failure with more actionable
information (just spent a lot of time trying to track down this problem :))

* ci: releases

* docs: minor update form @wjakob

* fix: enforce reasonable version of setuptools

* Initializing PyModuleDef object with PyModuleDef_HEAD_INIT.

Python 3.8 documentation: m_base - Always initialize this member to PyModuleDef_HEAD_INIT.

Long-standing (since first github commit in 2015), inconsequential bug.

Also removing inconsequential Py_INCREF(def): PyModule_Create() resets the reference count to 1.

* git rebase master

* moving static PyModuleDef declaration to global scope, as requested by @wjakob

* renaming the two new macros, to start with PYBIND11_DETAIL_MODULE

Fixed in #2510 but reintroduced on one line by #2126

Closes #2515, found by @rhjdjong

This changes enum reprs to look like `<Enum.name: value>` similarly to
the Python enum module.

This keeps the str of enums as `Enum.name`, like the Python enum module.

* Include what is used

* Separated the C++ standard library headers and the project headers

* Reordering includes

* fix: AppleClang 12 new warning

* Fix: AppleClang X.X.0 will not trigger this warning

* ci: fix broken documenation test (works on RtD)

* docs: docs link incorrect

* docs: read version from pybind11 file

* docs: show full PEP 440 version everywhere

This now tests the old form too, and fixes the bug introduced.