[QtonPi] strange error building wayland

[JC]

It looks like qtsync calls an alpha version in the raspbian distribution 
(according to Laszlo remark), but this does not come from me : I've 
installed qt5 following the wiki recommendations and all the sources 
came from git. In addition, this call  is really strange. It is in my 
/opt/qt5/bin/qtsync script, but have not created it and I would not know 
what to put instead inside...

What's the best way to upgrade the script without tearing down my whole 
install ;) ?

Rgds
JC