Update to 3.7.9 and use latest macOS SDK to fix Qt crash

[rggjan]

Updating python to 3.7.9 and applying the changes here:
#412

Would fix this isse:
conda-forge/pyside2-feedstock#46

and Qt crashing on macOS Big Sur...

[isuruf]

#462 should fix this issue for python 3.8 and 3.9 is already fixed. @rggjan, are you still using python 3.7?

[rggjan]

Yes, unfortunately I'm stuck with 3.7 due to other dependencies for now...

[rggjan]

Good to know 3.8 is also fixed, though!

[isuruf]

Is this bug on Big Sur only or on 10.15 too?

[rggjan]

I think only Big Sur...

[rggjan]

(At least the crash...)

[mbargull]

FYI, gh-462 seemed to have caused some kind of regression in at least one case for 3.8: conda-forge/cctbx-base-feedstock#22 (3.9 builds work fine, though).

[isuruf]

3.7 support is now dropped