BUG: ndimage.value_indices: deal with unfixed types

[tylerjereddy]

• Fixes BUG: scipy.ndimage.value_indices returns empty dict for intc/uintc dtype on Windows #19423

• Add a few more case statements to account for the (i.e., Windows) data types that don't have a fixed width, and add a regression test.

[skip circle] [skip cirrus]

[tylerjereddy]

ah right, I'll need preprocessor guards or something similar, that's fun

[tylerjereddy]

That's a little closer, but 32-bit Linux failure is real. I could probably skip that case and argue we're still doing better than main, but I should probably do a better/more complete fix I suppose.

[tylerjereddy]

Alright, this seems to be portable now, and CI is passing. There may be a more elegant solution, though the patch isn't too big anyway.

[neilflood]

Thanks @tylerjereddy

I wrote the original switch statements, and had no idea that these generic names had such different behaviour on Windows. Thanks for rescuing that, much appreciated. :-)

[tylerjereddy]

@grlee77 are you happy for this to be merged? I don't usually add shims to ndimage, but looks like original author of these code blocks is happy.

[tylerjereddy]

I'm going to take the approval of the original author of the code as a substitute/"next best thing" for core dev approval and self-merge this ahead of the 1.13.1 release. Ping me if you're not happy about that. The CI is passing, it has a regression test, and the patch is small.