Co-authored-by: binbjz <binbjz@gmail.com>

Citing https://www.postgrespro.ru/list/id/E1kfzRR-0001EH-Ph@gemulon.postgresql.org
fixing the same problem:
We previously put the -isysroot switch only into CPPFLAGS, theorizing
that it was only needed to find the right copies of include files.
However, it seems that we also need to use it while linking programs,
to find the right stub ".tbd" files for libraries.  We got away
without that up to now, but apparently that was mostly luck.  It may
also be that failures are only observed when the Xcode version is
noticeably out of sync with the host macOS version; the case that's
prompting action right now is that builds fail when using latest Xcode
(12.2) on macOS Catalina, even though it's fine on Big Sur.

Specifically, the problem arises for `preadv' and `pwritev' (new in MacOS 11 Big Sur) when building with XCode 12.4 (supporting Big Sur) in MacOS 10.15 Catalina.

Bumps the github-actions group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `actions/checkout` from 5 to 6
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

> The macOS 13 Ventura based runner images will begin deprecation on September 22nd and will be fully unsupported by December 4th for GitHub and ADO.

https://github.com/actions/runner-images/issues/13046

Signed-off-by: Edgar Ramírez Mondragón <edgarrm358@gmail.com>

https://www.gnu.org/server/mirror.html advises
to use http://ftpmirror.gnu.org/
for automatic mirror selection

Use tclConfig.sh/tkConfig.sh for future-proofing
3.14.0 doesn't detect Tcl/Tk with external libtommath, have to do it ourselves

---------

Co-authored-by: Ivan Pozdeev <vano@mail.mipt.ru>

Use TCLTK_* and pkg-config for 3.11+ linking with Homebrew Tcl/Tk; add PYTHON_BUILD_TCLTK_FORMULA envvar

Tcl/Tk 9.0 support was added in 3.13.0b3 and is not official as of 3.14.0;
the build with Homebrew version fails as of this writing

Fixes warnings "configure: WARNING: unrecognized options: --with-tcltk-libs, --with-tcltk-includes"

fix script

Add CPython 3.14.0rc3

Apple CLang excludes it if -isysroot is passed

- pip
- pipX
- pipX.Y
- * -m pip

Co-authored-by: Christian Fredrik Johnsen <christian@johnsen.no>

Bats test suite in docker

use global setup with bats with possibility to add specific test file _setup
use readlink in helper if realpath is not working as expected

fix bats warnings