Bug#902472: sdl2: can deadlock after hiding a window

[ydirson at free.fr]

Package: libsdl2
Version: 2.0.5+dfsg1-3
Tags: stretch patch

It can happen that SDL gets stuck waiting for X to accept a grab request, when the
window has already been hidden with SDL_HideWindow.

This behaviour has been fixed in 2.0.6 with commit 8f0a002 "x11: Don't loop forever
if the X server refuses a pointer grab", and does fix the problem for me when cherry-picking
that commit.

It would be great if that patch could find its way in a stretch update.  In any case since
it would take some time to get the fix to users, it would be good to get a backport to point
impacted users to.  Would you mind if I uploaded a 2.0.8 backport ?