Revision control
++ Qt 5.9 introduces many new features and improvements as well as bugfixes
++ over the 5.8.x series. For more details, refer to the online documentation
++ included in this distribution. The documentation is also available online:
++
++
++ With the exception noted below, the Qt version 5.9 series is binary compatible
++ with the 5.8.x series. Applications compiled for 5.8 will continue to run with 5.9.
++
++ Some of the changes listed in this file include issue tracking numbers
++ corresponding to tasks in the Qt Bug Tracker:
++
++
++ Each of these identifiers can be entered in the bug tracker to obtain more
++ information about a particular change.
++
++ Important Changes
++ -----------------
++
++ * Binary compatibility breakage in QtWaylandCompositor.
++
++ The class QWaylandQuickOutput now also inherits from QQmlParserStatus. This class
++ is primarily useful from QML, and there is little reason for it to used in
++ user C++ code. Any compositor using or instantiating the QtWaylandCompositor class
++ from C++ will have to be recompiled against Qt 5.9. Failure to do so may lead to crashes,
++ buffer overruns, or undefined behavior.
++
++ Client
++ ------
++
++ - Added xdg_shell_v6 support for Qt clients.
++
++ - Clients now default to using xdg_shell_v6 if available, else wl_shell.
++
++ - Deprecated the QT_WAYLAND_USE_XDG_SHELL environment variable in favor of
++ QT_WAYLAND_SHELL_INTEGRATION, which can be set to one of [ivi-shell, wl-shell,
++ xdg-shell-v5, xdg-shell-v6].
++
++ - Fixed crash when the receiver of a paste closes the pipe.
++
++
++ Compositor
++ ----------
++
++ - QWaylandQuickOutput: Automatically set the compositor if output is a child of
++ the compositor.
++
++ - QWaylandXdgSurfaceV5 now sets the windowType property and behaves like
++ other shell surface implementations.
++
++ - QWaylandXdgPopupV5 position property now has change notification.
++
++ - [QTBUG-55303] Added support for running compositors with custom device pixel ratio.
++
++ - [QTBUG-58299] Fixed wayland-egl compositing using NVIDIA graphics.