Cannot use pyenv-installed python due to missing library

On my system, I installed a version of python using pyenv. The version of python is compiled by pyenv from source against libraries in the system, as normal

Visual Studio code cannot find this version of python. Looking at the logs I see:

```
Error 2020-08-19 01:13:50: Failed to get interpreter information for '/home/valmar/.pyenv/versions/om-py3/bin/python3' [Error: Command failed: "/home/valmar/.pyenv/versions/om-py3/bin/python3" "/home/valmar/.var/app/com.visualstudio.code/data/vscode/extensions/ms-python.python-2020.8.101144/pythonFiles/pyvsc-run-isolated.py" "/home/valmar/.var/app/com.visualstudio.code/data/vscode/extensions/ms-python.python-2020.8.101144/pythonFiles/interpreterInfo.py"
/home/valmar/.pyenv/versions/om-py3/bin/python3: error while loading shared libraries: libcrypt.so.2: cannot open shared object file: No such file or directory
```

libcrypt is installed in my system, but no in the Flatpak. Pyenv is quite a commonly used program. Would it be possible please to install the library in the flatpak?

まず、issueに示されているpyenv実行ファイルについてインタープリターの検出を再現し、Flatpak環境でlibcrypt.so.2を調べます。Visual Studio Codeが、このpyenvでインストールされたPythonから、ライブラリが見つからないエラーなしにインタープリター情報を取得できれば完了です。

索引モデルが issue の本文から書いたものです。