iOS testbed doesn't honor .pth files

[freakboy3742]

Bug report

Bug description:

When running tests through the iOS testbed, .pth files that are installed by packaged (such as the setuptools "distutils_hack") will not be processed.

This surfaced during testing of an iOS patch for Pillow, which uses pyroma; pyroma depends on distutils; but because the .pth file installed by setuptools isn't processed, distutils can't be imported, and so neither can pyroma.

CPython versions tested on:

3.13

Operating systems tested on:

Other

Linked PRs

• gh-135966: Modify iOS testbed to make app_packages a site directory #135967

[freakboy3742]

The fix for this is that the app_packages folder used to install dependencies needs to be processed as a site location. The code for this is already present in the Briefcase iOS template.

In addition to the testbed needing to be updated to do app package handling, the documentation advising on setting up an iOS interpreter (and the testing infrastructure) needs to be updated.