[PATCH setup] Show a MessageBox warning if running on a deprecated Windows version

[Jon Turney]

On 18/01/2022 16:15, Jon Turney wrote:
> On 14/01/2022 09:04, Corinna Vinschen wrote:
>> On Jan 13 15:13, Jon Turney wrote:
>>> Show a MessageBox warning if we are running on a Windows version which
>>> we have deprecated Cygwin support for:
>>>
[..]
>>
>> Question is, how often should setup show this message?  Every time might
>> really be a bit annoying.  Some kind of "I saw it, now leave me alone,
>> at least for a while" kind of function would be great.
> 
> Yeah, unfortunately that turns this into more effort than I'm going to 
> commit to this:
> 
> Adding a "Don't show this again" checkbox means we can't use a 
> MessageBox, so have design a dialog box for that purpose.
> 
> Making that setting persistent means we have to wait until after the 
> cygwin root directory is established so we know where to retrieve that 
> persistent setting from.

It turns out SHMessageBoxCheck() exists, which avoids both these 
problems, so I've reworked this change to use that.