qtdeclarative: Fix build with tests enabled

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
qtwayland: Fix xcomposite-glx and examples build

* egl was building fine, but glx was failing to find
  qwaylandintegration.h
* one example cannot be built without gles2, so make it
  conditional

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>