[Development] Windows 7 support future removal

[Shawn Rutledge]

> On 24 Aug 2018, at 08:24, Thiago Macieira <thiago.macieira at intel.com> wrote:
> 
> On Thursday, 23 August 2018 23:11:09 PDT Lars Knoll wrote:
>> We know that quite some users stay on unsupported versions of Windows for
>> quite a while. I wonder whether it wouldn’t be easiest in this case to then
>> drop Windows 7 with Qt 6.0 in Autumn 2020 (ie. in the release after 5.15).
> 
> I don't mind either way. I just wanted to bring the topic up.
> 
> I don't think we have much that requires Windows 8 or 8.1, which would result 
> in any meaningful clean up of our source code if we were to drop Windows 7. 
> We'd get rid of a few GetProcAddresses, but not a lot.

Pointer Input Messages (modern API for touch, touchpad, and tablet/stylus devices, recently added, see QTBUG-60437 and https://codereview.qt-project.org/#/c/230421/ ) are not supported in Windows 7 AFAIK.  So maybe there’s some room for simplification there eventually, FWIW.