Make xcb compile with X-less EGL implementations

On platforms like the Raspberry Pi the EGL implementation is not
compatible with X. This means that while EGL and Open GL ES can be enabled,
and will work fine with platform plugins like eglfs, EGL (and thus GL) should
be automatically disabled in xcb, otherwise a compilation error will occur
since xcb assumes the native handle types are the corresponding Xlib types.

Task-number: QTBUG-36551
Change-Id: I2cc4c558abb4b25d422a2c01da9b75b865ace402
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Do not set input focus if WM supports _NET_ACTIVE_WINDOW

In case the window manager supports _NET_ACTIVE_WINDOW a client message
is sent to the root window and the window manager is expected to either
activate the window or mark it with demands attention.

In addition the code unconditionally also called xcb_set_input_focus
which breaks the intention of sending the client message. Thus it is
now only done if the WM doesn't support the protocol. This was also the
logic in Qt 4.x in QWidget::activateWindow (qwidget_x11.cpp).

In addition set_input_focus is only called if the window is a toplevel.

Change-Id: Iec4c02f0ea62db30a4b347d474fdfd2f05b8895b
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>