Failure with more than one EGL-based client buffer integration

All the EGL-based client buffer integrations call eglBindWaylandDisplayWL, and by default fail to initialize if it returns false. However, "eglBindWaylandDisplayWL returns EGL_FALSE when there is already a wl_display bound to EGLDisplay otherwise EGL_TRUE". This means that only the first integration will work. One workaround is to set  the environment variable QT_WAYLAND_IGNORE_BIND_DISPLAY