I can't figure out how to build it with cross compiler (on trusty-amd64 for utopic-armhf):
dpkg-buildpackage -rfakeroot -b -aarmhf
that gives some unsatisfied dependencies: libasound2-dev libgstreamer-plugins-base0.10-dev libgstreamer0.10-dev libpulse-dev libqt5opengl5-dev (>= 5.3.0+dfsg~) qtbase5-dev (>= 5.3.0+dfsg~) qtbase5-private-dev (>= 5.3.0+dfsg~) qtdeclarative5-private-dev (>= 5.3.0~) zlib1g-dev libqt5sql5-sqlite (>= 5.3.0+dfsg~) qttools5-dev-tools (>= 5.3.0~)
I tried to get libasound2-dev:armhf and libgstreamer-plugins-base0.10-dev:armhf, but both conflict with host packages. For example libasound2-data:armhf and libasound2-data don't coexist.
Cross in chroot
Then I tried amd64 utopic chroot, but failed to install crossbuild-essential-armhf in it. Same with trusty-amd64 chroot. It gives: crossbuild-essential-armhf : Depends: libc6-dev:armhf but it is not going to be installed Just like here: https://answers.launchpad.net/ubuntu/+source/build-essential/+question/250970 But editing sources.list doesn't change anything at all.
So I thought that is is not how it's done.
Next thing was armhf chroot. But there is a problem with qmake there: https://bugs.launchpad.net/ubuntu/+source/click/+bug/1393697
What is the right way to build an utopic armhf deb?