Building wayland-egl compositor without X11 fail

If Qt is not built against X11 support, wayland-egl compositor build fail with error : missing X11/Xlib.h

This can be fixed adding egl in QMAKE_USE_PRIVATE in src/plugins/hardwareintegration/compositor/wayland-egl/wayland-egl.pro

— bellow compilation log

/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/bin/arm-buildroot-linux-gnueabihf-g++ -c -pipe -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O2 --sysroot=/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot -O2 -O3 -std=c+1z -fvisibility=hidden -fvisibility-inlines-hidden -fno-exceptions -Wall -W -Wvla -Wdate-time -Wshift-overflow=2 -Wduplicated-cond -D_REENTRANT -fPIC -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_PLUGIN -DQT_WAYLANDCOMPOSITOR_LIB -DQT_QUICK_LIB -DQT_EGL_SUPPORT_LIB -DQT_GUI_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -I. -I../../../../hardwareintegration/compositor/wayland-egl -I../../../../../include/QtWaylandCompositor/5.10.0 -I../../../../../include/QtWaylandCompositor/5.10.0/QtWaylandCompositor -I../../../../../include -I../../../../../include/QtWaylandCompositor -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtQuick/5.10.0 -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtQuick/5.10.0/QtQuick -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5 -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtQuick -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtEglSupport -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtEglSupport/5.10.0 -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtEglSupport/5.10.0/QtEglSupport -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtGui/5.10.0 -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtGui/5.10.0/QtGui -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtGui -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtQml/5.10.0 -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtQml/5.10.0/QtQml -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtQml -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtNetwork -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtCore/5.10.0 -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtCore/5.10.0/QtCore -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtCore -I.moc -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include -I/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/mkspecs/devices/linux-buildroot-g+ -o .obj/waylandeglclientbufferintegration.o ../../../../hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
In file included from /home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/EGL/egl.h:39:0,
from /home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtEglSupport/5.10.0/QtEglSupport/private/qt_egl_p.h:65,
from /home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/qt5/QtEglSupport/5.10.0/QtEglSupport/private/qeglstreamconvenience_p.h:55,
from ../../../../hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp:56:
/home/jc/Projets/0000-buildroot/build/buildroot-linux-mainline-digi/host/arm-buildroot-linux-gnueabihf/sysroot/usr/include/EGL/eglplatform.h:118:22: erreur fatale : X11/Xlib.h : Aucun fichier ou dossier de ce type
#include <X11/Xlib.h>
^
compilation terminée.
Makefile:552 : la recette pour la cible « .obj/waylandeglclientbufferintegration.o » a échouée