This one gets rid of the extra "usr" subdirectory that we had and now fits the format that pyenv expects

We changed the directory structure for pyston 2.3.1 slightly, where we now
include a top-level "pyston-2.3.1" directory when you unpack the tarball.

* feat(python-build): allow tcl-tk as argument or default to homebrew
* refactor(python-build): detect tcl-tk-libs from confugre_opts_arr

* Disable coreutils on arm64-apple
* Only selectively apply to the affected CPython versions

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

Ensuring that all dirs in LDFLAGS exist is only needed for Ruby due to its `configure` requirements.
If some LDFLAGS entries point to a nonexisting path to which the user doesn't have permission. this causes a build failure.

The $(type -p | head -1) construct expects to always get a path, so need to ignore such aliases with -P

Closes https://github.com/pyenv/pyenv/issues/1662

E.g. "*-latest"
May need splitting into project-specific ones if there emerge projects with different check needed

Closes https://github.com/pyenv/pyenv/issues/1559

In certain cases, a user wants to know the cached filename to add the file themselves,
see https://github.com/pyenv/pyenv/issues/1743 .
Since we report both a filename and a URL anyway, there's no reason to report a wrong one.

This behavior is only triggered when the version is provided as an empty string,
is undocumented and breaks if multiple local versions are specified
(rightly so since it's unclear which of them to install).

The bootstrap.pypa.io URLs for pip installation changed.

Added aarch64 for Linux in anaconda_architecture()

Added aarch64 for Linux in anaconda_architecture()

fixes #1805

Fix pyenv to continue to support legacy Python builds despite the fact that `get-pip` has dropped support for Python 2 as discussed in pypa/get-pip#87

* Update python-build with arm64 architecture

Add LDFLAGS for Xcode SDK zlib on macOS >= 1100 to resolve build issues on Big Sur.

* Remove Ruby references from python-build

* restore fix_directory_permissions

This PR fixes (currently harmless) warning on macOS when homebrew is *not* installed.

- [ ] Test case (required?)

For example:

```sh
wadkar$ pyenv install 3.8.2
/Users/wadkar/.pyenv/plugins/python-build/bin/python-build: line 1541: brew: command not found
/Users/wadkar/.pyenv/plugins/python-build/bin/python-build: line 1541: brew: command not found
Installing openssl-1.1.0j...
Installed openssl-1.1.0j to /Users/wadkar/.pyenv/versions/3.8.2

Installing readline-8.0...
Installed readline-8.0 to /Users/wadkar/.pyenv/versions/3.8.2

Installing Python-3.8.2...
python-build: use zlib from xcode sdk
Installed Python-3.8.2 to /Users/wadkar/.pyenv/versions/3.8.2
```

The official pypy builds should now be portable on linux.
Also add aarch64 builds.

fixes #1219, #1333

This reverts commit 070e1c859fb2584c3dbe0a6fbe58cbc80938654e, reversing
changes made to 3faeda67bb.