$ cd qtconnectivity/examples
$ make
make
cd bluetooth/ && ( test -e Makefile || .../host/bin/qmake -o Makefile .../build/qt5connectivity-5.9.2/examples/bluetooth/bluetooth.pro ) && make -f Makefile
make[1]: Entering directory '.../build/qt5connectivity-5.9.2/examples/bluetooth'
cd heartrate-server/ && ( test -e Makefile || .../host/bin/qmake -o Makefile .../build/qt5connectivity-5.9.2/examples/bluetooth/heartrate-server/heartrate-server.pro ) && make -f Makefile
Project ERROR: Unknown module(s) in QT: gui
make[1]: *** [Makefile:45: sub-heartrate-server-make_first] Error 3
make[1]: Leaving directory '.../build/qt5connectivity-5.9.2/examples/bluetooth'
make: *** [Makefile:46: sub-bluetooth-make_first] Error 2