First reported at https://github.com/numpy/numpy/issues/18720

After upgrading to Python 3.9.3, 32-bit on Windows, importing numpy (installed via `pip install numpy`) crashes:

```
Microsoft Windows [Version 10.0.19041.906]
C:\Python39-32>python -X dev
Python 3.9.3 (tags/v3.9.3:e723086, Apr  2 2021, 11:01:03) [MSC v.1928 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy
Windows fatal exception: access violation

Current thread 0x0000105c (most recent call first):
  File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
  File "<frozen importlib._bootstrap_external>", line 1116 in exec_module
  File "<frozen importlib._bootstrap>", line 680 in _load_unlocked
  File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
  File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
  File "<frozen importlib._bootstrap_external>", line 1116 in exec_module
  File "<frozen importlib._bootstrap>", line 680 in _load_unlocked
  File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
  File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
  File "<frozen importlib._bootstrap_external>", line 1116 in exec_module
  File "<frozen importlib._bootstrap>", line 680 in _load_unlocked
  File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
  File "C:\Python39-32\lib\site-packages\numpy\random\_pickle.py", line 1 in <module>
  File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
  File "<frozen importlib._bootstrap_external>", line 790 in exec_module
  File "<frozen importlib._bootstrap>", line 680 in _load_unlocked
  File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
  File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1058 in _handle_fromlist
  File "C:\Python39-32\lib\site-packages\numpy\random\__init__.py", line 179 in <module>
  File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
  File "<frozen importlib._bootstrap_external>", line 790 in exec_module
  File "<frozen importlib._bootstrap>", line 680 in _load_unlocked
  File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
  File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1058 in _handle_fromlist
  File "C:\Python39-32\lib\site-packages\numpy\__init__.py", line 156 in <module>
  File "<frozen importlib._bootstrap>", line 228 in _call_with_frames_removed
  File "<frozen importlib._bootstrap_external>", line 790 in exec_module
  File "<frozen importlib._bootstrap>", line 680 in _load_unlocked
  File "<frozen importlib._bootstrap>", line 986 in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 1007 in _find_and_load
  File "<stdin>", line 1 in <module>
```

Rebuilding numpy from source against Python 3.9.3 fixes this crash, but many other packages compiled against older versions of Python 3.9.x still crash.

I think this might be due to <https://github.com/python/cpython/commit/8b795ab5541d8a4e69be4137dfdc207714270b77#diff-7285576bdacf86fe37274d3d0d399c29b4be2959005f60ac0729615d8fca9186>.

In `bpo-42500: Fix recursion in or after except (GH-23568) (#24501)`, the public `PyThreadState` struct changed. This breaks ABI compatibility for code that is directly accessing the `PyThreadState` struct members, which is not uncommon. E.g. in Cython <https://github.com/cython/cython/blob/0.29.x/Cython/Utility/Exceptions.c#L93-L115>. This code will fail on 32-bit. On 64-bit it passes because of fortunate struct alignment AFAICT.