shadow fails to cross-build

shadow fails to cross-build due to failing to find libpam

checking for pam_start in -lpam... no
configure: error: libpam not found
make: *** [debian/stamp-autotools] Error 1
dpkg-buildpackage: error: debian/rules build gave error exit status 2

However, libpam0g and -dev cross-packages are installed:
dpkg-cross -a armel -A -M -b -X multiarch-support -X debconf -X debconf-2.0 -X libpam0g-util libpam0g_1.1.2-2ubuntu8_armel.deb libpam0g-dev_1.1.2-2ubuntu8_armel.deb
Building libpam0g-dev-armel-cross_1.1.2-2ubuntu8_all.deb
dpkg-deb: building package `libpam0g-dev-armel-cross' in `./libpam0g-dev-armel-cross_1.1.2-2ubuntu8_all.deb'.
dpkg-cross: Multi-Arch package detected; processing anyway as --convert-mulitarch specified.
Building libpam0g-armel-cross_1.1.2-2ubuntu8_all.deb
dpkg-deb: building package `libpam0g-armel-cross' in `./libpam0g-armel-cross_1.1.2-2ubuntu8_all.deb'.

sudo apt-get -y --allow-unauthenticated -o Dir::State::Lists=/home/wookey/testing/build/build/xdeb/lists.apt -o Dir::Cache::pkgcache=/home/wookey/testing/build/build/xdeb/pkgcache.bin -o Dir::Cache::srcpkgcache=/home/wookey/testing/build/build/xdeb/srcpkgcache.bin -o Dir::Etc::sourcelist=/home/wookey/testing/build/build/xdeb/sources.list --no-install-recommends install libpam0g-dev-armel-cross libselinux1-dev-armel-cross

But for some reason that's not sufficient.