Revert to zlib on macOS < 10.15 by radarhere · Pull Request #8772

Revert to zlib on macOS < 10.15 by radarhere · Pull Request #8772 · python-pillow/Pillow

#8500 switched to zlib-ng in our wheels. However, #8750 has reported that wheels now segfault on macOS 10.13 and 10.14.

zlib-ng/zlib-ng#1877 was created to investigate this, and there is now a proposed fix in zlib-ng/zlib-ng#1878.

However, in case it is not merged and released before Pillow 11.2.0, this PR temporarily reverts to using zlib on macOS < 10.15.