Component
PyDIP 3.4.0.

Describe the bug
Importing pyfftw and diplib in the same process, and having diplib try to access its own internal fftw library, can lead to segfaults.

To Reproduce

$ python -c 'import pyfftw, numpy as np, diplib as dip; dip.GaussFT(np.zeros((139, 217)), 3, [1, 1])'
Fatal Python error: Segmentation fault

(the array size above is just some awkward numbers to trigger the use of fftw)

System information:

• What OS do you have? macSO 13.4.1
• If PyDIP, what version of Python do you have? 3.11
• If DIPimage, what version of MATLAB do you have? (type ver at the MATLAB command prompt, and copy-paste the result here). N/A
• If compiled from sources, what compiler and version did you use? N/A

Note: pyFFTW was installed from their git HEAD (pip install git+https://github.com/pyFFTW/pyFFTW) as their latest release does not support py3.11 AFAICT.

I suspect we end up with two copies of fftw with incompatible ABIs which step onto another...