jcal fails to cross build from source, because it does not pass --host
to configure. The easiest way of doing so is using dh_auto_configure. I
went slightly beyond that and converted all of the debhelper overrides
to use dh_auto_*. Note that dh_auto_configure also passes a multiarch
libdir and therefore libraries move to multiarch locations. I've updated
the *.install files accordingly. Please consider applying the attached
patch.

Helmut