https://bugzilla.redhat.com/show_bug.cgi?id=1483300
--- Comment #8 from Robert-André Mauchin zebob.m@gmail.com --- You download the source of qtbase in version 5.7.1 but here:
cp qtbase-opensource-src-%{_qt5_version}/src/plugins/platforms/xcb/*.h \ platformplugin/libqt5xcbqpa-dev/
you use %{_qt5_version} which is not always 5.7.1: on Rawhide it replaces %{_qt5_version} with 5.9.1 so it can't work.
I think you should download the qtbase 5.9.1 instead of 5.7.1 and not use %{_qt5_version}