When qt5 repository is cloned and dev branch is checked out:

cd qt5
git checkout dev
git pull --rebase
git submodule --update --init recursive

During following module builds:

qtbase. qtdeclarative, qtxmlpatterns, qtquickcontrols2

Multiple errors of undefined reference to 'qml...'_  were causing during qtquickcontrols2 build, as an example:

qt5/qtquickcontrols2/src/imports/controls/basic/qtquickcontrols2basicstyleplugin.cpp
qt5/qtquickcontrols2/src/imports/controls/fusion/qtquickcontrols2fusionstyleplugin.cpp:64: error: undefined reference to 'qml_register_types_QtQuick_Controls_Fusion()'
clang++: error: linker command failed with exit code 1 (use -v to see invocation)