bug#5482: frame-invisible-p reports nil for iconified frames on w32

[Eli Zaretskii]

> Date: Mon, 27 Jun 2016 18:56:23 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: ahyatt@gmail.com, lennart.borgman@gmail.com, 5482@debbugs.gnu.org
> 
>  > On Windows 7, calling iconify-frame doesn't cause the frame to show
>  > when the mouse pointer hovers above the Emacs icon on the task bar, as
>  > if the frame is still invisible.  No such problem on XP, though.
> 
> Aha.  Windows is getting picky.  Would
> 
>    my_show_window (f, FRAME_W32_WINDOW (f), SW_SHOWMINNOACTIVE);
> 
> instead of
> 
>    SendMessage (FRAME_W32_WINDOW (f), WM_SYSCOMMAND, SC_MINIMIZE, 0);
> 
> in x_iconify_frame fix it?

I don't know enough about this to tell.  (Why SW_SHOWMINNOACTIVE and
not SW_SHOWMINIMIZED?)

But if this seems to fix the issue, feel free to push to master.

Thanks.