[Bug 58209] add an environmental variable to control the Windows Version

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=58209

--- Comment #2 from ToastyBug  ---
(In reply to Nikolay Sivov from comment #1)
> You'll have to relaunch anyway, but you can use "winecfg /v winxp" from
> command line already, to avoid going through UI.
>
> Then you can configure different version reported for a given exe file you
> run, if you need this change set permanently for some application.

Thank you, I was able to figure out the options
> Usage: winecfg [options]
>
> Options:
>   [no option] Launch the graphical version of this program.
>   /v          Display the current global Windows version.
>   /v version  Set global Windows version to 'version'.
>   /?          Display this information and exit.
>
> Valid versions for 'version':
>    win11  Windows 11
>    win10  Windows 10
>    win81  Windows 8.1
>     win8  Windows 8
>
> win2008r2  Windows 2008 R2
>         win7  Windows 7
>      win2008  Windows 2008
>        vista  Windows Vista
>      win2003  Windows 2003
>      winxp64  Windows XP 64
>        winxp  Windows XP
>        win2k  Windows 2000
>        winme  Windows ME
>        win98  Windows 98
>        win95  Windows 95
>         nt40  Windows NT 4.0
>        nt351  Windows NT 3.51
>        win31  Windows 3.1
>        win30  Windows 3.0
>        win20  Windows 2.0

So I could launch an app with:
winecfg /v winxp && wine my-old-program.exe