On non-compositing window managers, XIconifyWindow can trigger map/unmap events, which would toggle the window hidden/shown state. This should not be done, as a hidden window in SDL is equivalent to a withdrawn window in X, and SDL will try to set/reset state when it is shown again.
Unless the window is explicitly being withdrawn via X11_HideWindow(), set unmapped windows to the minimized/occluded state, and send a restored event when mapped again.
(cherry picked from commit 667b706a93)