Have GalSim support Windows installations.

[RomanAkhmetshyn]

OS: Windows 10
Python 3.9.7
Anaconda environment
all requirements installed
When trying to install galsim with pip I run into an error:

File "C:\Users\Admin\anaconda3\lib\genericpath.py", line 42, in isdir
        st = os.stat(s)
    TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType

Full PowerShell output in .txt file included
powershell_output.txt

[rmandelb]

As per https://github.com/GalSim-developers/GalSim/blob/releases/2.3/INSTALL.rst , we do not currently support installation on Windows, so this kind of error is expected.

[rmjarvis]

That said, I recently figured out what was needed to get things working in Windows for TreeCorr. cf. rmjarvis/TreeCorr#143 So maybe we can leave this open and I'll hack on it in from time to time.

[andrevitorelli]

On a side note, GalSim does work fine in WSL in Windows machines.