xkbcommon should not be a mandatory dependency

Not all platforms that use qtwayland depend on xkbcommon to be present
for them to be functional

Change-Id: I9dcc8f661f7d6035f405420d9d4733b52c77112e
Reviewed-by: Andy Nichols <andy.nichols@digia.com>
Fix shader precision qualifier

On some stricter platforms this will cause problems in compiling
the shader code

Change-Id: I466e2ed231be9d414c9a3ffdb15ff67186933162
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
remove QWindowSystemInterface::flushWindowSystemEvents()

Change-Id: I88e83f4490f98752e827c743405b7f62e1910902
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
Use shared .pri file for wayland_common and GL integrations

wayland_common.pro missed pkg-config for xkbcommon.
But wayland-common.pri has it. Actually, Both the .pro and the .pri
has many identical configurations. Make it to share
wayland_common_share.pri for those configuations including xkbcommon
to build wayland_common and GL integrations.

Change-Id: I397592eae482976c18d3e86bd8e0427a5f219d06
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Set an initial size to the window if it is empty

Change-Id: Ib3e8a4b69ef855be45ad1ad987975697d262c739
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
Reviewed-by: Andy Nichols <andy.nichols@digia.com>
Make QWindowCompositor render when surfaces move around

Change-Id: I1f363238232c145941940fe203b110f8855d8c26
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
Calling damage on a surface from the compositor api doesn't make sense

It will not cause the damaged signal to be emitted

Change-Id: Ifb8265811d432d80bd6d84469d5c673b62d65290
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
Don't create wl_shell_surface if BypassWinowManagerHint is set

Custom window types might want to set BypassWinowManagerHint and use
the native Wayland API together with the platform native interface.
In this case wl_shell_surface won't be used.

Change-Id: I66d50fc89901e4ff513b8979d08d7ad7d37f817e
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Merge remote-tracking branch 'upstream/stable' into hawaii-stable

Conflicts:
	src/plugins/platforms/wayland_common/qwaylandwindow.cpp