Because most Python packages maintain tests in top-level directory
`tests/` instead of `test/`, add both to source distributions for
consistency.

C99 removed support for implicit function declarations.  This means
that just calling a function, without declaring the function first,
can result in a compilation error.  Today, has_function works with
most compilers because they issue just a warning, create an object
file, and attempt a link, which then detects available of the symbol
at link time, as intended.  With future compilers, compilation will
already fail, and no link test is performed.

The has_function interface provides the caller with a way to supply
a list of header files to include.  However, even with today's
compilers, this only works if the function does not expect any
parameters.  Otherwise, the function call in the C fragment created
by has_function will not supply the correct argument list and fail
compilation.  Therefore, this change supplies and incorrect prototype
without arguments.  This is what autoconf does today in a very
similar situation, so it is quite likely that compilers will support
this construct in this context in the future.

The includes and include_dirs arguments are deprecated because of
the parameter list mismatch issue.

Fixes #3648.

[FURB123]: Replace `str(x)` with `x`

[FURB113]: Use `x.extend(...)` instead of repeatedly calling `x.append()`

[FURB108]: Use `x in (y, z)` instead of `x == y or x == z`

[FURB131]: Replace `del x[y]` with `x.pop(y)`

[FURB109]: Replace `in [x, y, z]` with `in (x, y, z)`

…ig. Fixes pypa/distutils#178.

Link directly to PEP

Apply refurb suggestions

Update outdated GitHub Actions

For 'get_python_inc', bypass missing config include dir

Fix MinGW-w64 segmentation fault

Fix typos found by codespell

Add `tests/test*.py` to source distributions

distutils.ccompiler: Make has_function work with more C99 compilers

This reverts commit 0171aee, reversing
changes made to fb2a173.

- fixes #3591

The previous code did not take into account the .exe file extension
on Windows.

Fix MinGW-w64 segmentation fault (v2)

distutils.ccompiler: Remove correct executable file on Windows

add a pypy CI run

Fixed accumulating include dirs after compile