Trouble making a .deb package from Qt4 project. dpkg-buildpackage attempts to use Qt5 - while I specify Qt4 every time?

[Andse]

The project compiles fine, I use

@qmake-qt4 qgroundcontrol.pro
make@

now, I try to make a debian package:
I do:
@dh_make -s -c gpl -e myEmailAddress --createorig@
it completes fine, dependencies are missing, but overall it's fine.
I say:
@dpkg-buildpackage@

it works for a while, then fails, with an attempt to use qmake(qt5)
@
dpkg-source: warning: ignoring deletion of file build-release/obj/cache.o
dpkg-source: warning: ignoring deletion of file build-release/obj/ParamCompareDialog.o
dpkg-source: warning: ignoring deletion of file src/ui/WaypointList.cc.orig
dpkg-source: info: building apmplanner in apmplanner_2.0b2-1.debian.tar.gz
dpkg-source: info: building apmplanner in apmplanner_2.0b2-1.dsc
debian/rules build
dh build
dh_testdir
dh_auto_configure
Usage: /usr/lib/x86_64-linux-gnu/qt5/bin/qmake [mode] [options] [files]

QMake has two modes, one mode for generating project files based on
some heuristics, and the other for generating makefiles. Normally you
shouldn't need to specify a mode, as makefile generation is the default
mode for qmake, but you may use this to test qmake on an existing project
@