Undefined reference to content::MediaStreamDeviceObserver::AddStream

1) Qt fails to build with following errors:

[14877/14877] touch QtWebEngineCore.stamp
/home/appimage/appimage-workspace/deps-build/ext_qt/ext_qt-prefix/src/ext_qt-build/qtwebengine/src/core/release/obj/content/renderer/librenderer.a(pepper_media_device_manager.o):pepper_media_device_manager.cc:function content::PepperMediaDeviceManager::OnDeviceOpened(int, bool, std::string const&, content::MediaStreamDevice const&): error: undefined reference to 'content::MediaStreamDeviceObserver::AddStream(std::string const&, content::MediaStreamDevice const&)'
collect2: error: ld returned 1 exit status
make[8]: *** [../../lib/libQt5WebEngineCore.so.5.11.2] Error 1

2) We've got CI system that builds Qt and the log can be seen here

https://binary-factory.kde.org/job/KMyMoney_Nightly_Appimage_Dependency_Build/34/consoleText

3) I build Qt by ExternalProject_Add (see attachment for exact configuration)

Whole build system can be seen here

https://cgit.kde.org/kmymoney.git/tree/3rdparty

and here

https://cgit.kde.org/kmymoney.git/tree/packaging/linux/appimage