add `shared` config to build Python shared library

[adehad]

I was trying to use this devcontainer with PyInstaller, and it seems like the build fails due to the Python installation not built with the shared libraries.

Summary of Changes

1. Provides a new option to control the build flag for the shared libraries

Concerns / Thoughts

1. Do we want to preserve the original behaviour (ie have the option as false)
2. Do we want to do something special regarding the MacOS specific commands

Details

Here are the relevant logs

    run()
  File "/workspaces/pyside6-boilerplate/.venv/lib/python3.12/site-packages/PyInstaller/__main__.py", line 198, in run
    run_build(pyi_config, spec_file, **vars(args))
  File "/workspaces/pyside6-boilerplate/.venv/lib/python3.12/site-packages/PyInstaller/__main__.py", line 69, in run_build
    PyInstaller.building.build_main.main(pyi_config, spec_file, **kwargs)
  File "/workspaces/pyside6-boilerplate/.venv/lib/python3.12/site-packages/PyInstaller/building/build_main.py", line 1071, in main
    build(specfile, distpath, workpath, clean_build)
  File "/workspaces/pyside6-boilerplate/.venv/lib/python3.12/site-packages/PyInstaller/building/build_main.py", line 1011, in build
    exec(code, spec_namespace)
  File "app.spec", line 13, in <module>
    a = Analysis(
        ^^^^^^^^^
  File "/workspaces/pyside6-boilerplate/.venv/lib/python3.12/site-packages/PyInstaller/building/build_main.py", line 470, in __init__
    self.__postinit__()
  File "/workspaces/pyside6-boilerplate/.venv/lib/python3.12/site-packages/PyInstaller/building/datastruct.py", line 184, in __postinit__
    self.assemble()
  File "/workspaces/pyside6-boilerplate/.venv/lib/python3.12/site-packages/PyInstaller/building/build_main.py", line 581, in assemble
    raise PythonLibraryNotFoundError()
PyInstaller.exceptions.PythonLibraryNotFoundError: Python library not found: libpython3.12.so, libpython3.12.so.1.0
    This means your Python installation does not come with proper shared library files.
    This usually happens due to missing development package, or unsuitable build parameters of the Python installation.

    * On Debian/Ubuntu, you need to install Python development packages:
      * apt-get install python3-dev
      * apt-get install python-dev
    * If you are building Python by yourself, rebuild with `--enable-shared` (or, `--enable-framework` on macOS).

[adehad]

@microsoft-github-policy-service agree

[joshspicer]

Would you mind adding a scenario test to exercise your new flag (docs)?

[adehad]

Would you mind adding a scenario test to exercise your new flag (docs)?

Of course, my bad for missing this.

any preference for using an ldd command (nix specific)

root@c098cfd1b2e0:/workspaces/python# ldd $(which python)
        linux-vdso.so.1 (0x00007fff0a3fb000)
        libpython3.12.so.1.0 => /usr/local/bin/../lib/libpython3.12.so.1.0 (0x00007f43580d5000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f4357ef8000)
        libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f4357ed6000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f4357ed0000)
        libutil.so.1 => /lib/x86_64-linux-gnu/libutil.so.1 (0x00007f4357ecb000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f4357d87000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f4358706000)

When not built with shared looks like:

['/usr/local/python/3.10.13/lib', 'libpython3.10.a']

or a Python only

root@c098cfd1b2e0:/workspaces/python# python -c "import sysconfig; print(sysconfig.get_config_vars('LIBDIR', 'INSTSONAME'))" 
['/usr/local/lib', 'libpython3.12.so.1.0']

I'll grep either with option with | grep 'libpython3.*so' in the check