Segfault under free-threaded build

[ngoldbaum]

See https://github.com/tonybaloney/pytest-freethreaded/issues/9 where this was discovered and for steps to reproduce.

Ultimately this comes down to the thread safety warnings in the freetype docs for FT_Face: https://freetype.org/freetype2/docs/reference/ft2-face_creation.html#ft_face. Somehow an FT_Face is being shared across threads in the test scenario linked above.

Ping @lysnikolaou

[radarhere]

It's strange that our Ubuntu GitHub Actions free-threaded job doesn't detect this error, isn't it? The error report is on macOS, maybe the error only occurs on that platform.

Edit: Oh, I see, you need to install pytest-freethreaded. Phase 2 of the README (--threads 1 --iterations 1) passes on Ubuntu, but Phase 3 (--require-gil-disabled) does not.