Automatically check for missing DLLs on Windows

[lithomas1]

closes #150

Merge for 1.4, since a rc would catch any problems here. This is a blocker since the Windows 2016 image is going away next year.

DLLS aren't checked on 32 bit since I cannot find a 32-bit python image on windows.

cc @simonjayhawkins

[simonjayhawkins]

Thanks @lithomas1

Merge for 1.4, since a rc would catch any problems here.

We don't have separate branches for 1.3.x and master in this repo (numpy does)

Can't we check the nightlies? (which are built from master)

On the last minor release cycle, 1.3rc was released before 1.2.5 (we can't guarantee that won't happen again)

[lithomas1]

Can't we check the nightlies? (which are built from master)

We can, but I don't have a clean Windows environment(my laptop has MSVC on it and is too old to run Docker containers).
We can also try merging this early for 1.3.5. 1.4 is less risk, since the DLL that was missing should be included with Python 3.8's files. I tested this manually by commenting out dlls, and the import did seem to fail without some DLLs, so it should work.

I'm not sure what to do about the lack of 32 bit images, though. Maybe we should open an issue on the main repo about dropping 32 bit support entirely?

[matthew-brett]

Maybe we should open an issue on the main repo about dropping 32 bit support entirely?

Just for reference - this was the latest I know of from the Microsoft / Python folks about 32-bit : scipy/scipy#14316 (comment)

[jreback]

@lithomas1 can u rebase

[auvipy]

why six?

[lithomas1]

Its a dependency of python-dateutil.