How to compile Qt with Bluetooth?

Question

linux

The bottom line is that I need to compile the modified qtconnectivity module , but it turned out that the original one doesn’t really want to work after compilation. Whereas the binaries work.
I did everything as it is written here:
https://wiki.qt.io/Building_Qt_5_from_Git/ru
in short:

unset QTDIR
export PATH="$PWD/qtbase/bin:$PWD/qtrepotools/bin:$PATH"
./configure -developer-build -opensource -nomake examples -nomake tests
./build -j 3

But for some reason I don't have a build file, so I ran this:
make module-qtconnectivity
Everything compiled, but on these binaries, when I try to run the lowenergyscanner example , it gives the following:

qt.bluetooth: Dummy backend running. Qt Bluetooth module is non-functional.

What am I doing wrong?