gtk on windows 10

[Kasper Peeters <kasper peeters phi-sci com>]

I have successfully compiled a previously linux-only gtk-based program
on Windows 10 using the vcpkg packages. Things run, but the look is not
good yet.

What is the up-to-date status of getting gtk apps on Windows 10 to look
as native as possible? I tried a etc\gtk-3.0\settings.ini file with
content

   [Settings]
   gtk-theme-name=win32

which does give things a Windows 7ish look, but all window decorations
(close/max/min) are broken and show the default 'grey picture' icon.
In fact, I get this problem with any theme, not just win32.
I am running gtk-3.22.19 (which is what is current in vcpkg).

So concretely:

  - What's the best way right now to get a Windows 10 look with gtk apps
    on Windows 10? Is there anything like builtin like 'win32' but with
    updated look? If not, what's the recommended theme?

  - How do I get the window decorations to show up properly? (do I need
    to install a theme engine or something like that?).

Thanks,
Kasper