hardinfo version 0.5.1-1.1ubuntu4 failed to build in oneiric

hardinfo version 0.5.1-1.1ubuntu4 failed to build in oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110816/+build/2695563

Details about the rebuild:
http://people.ubuntuwire.org/~wgrant/rebuild-ftbfs-test/test-rebuild-20110816-oneiric.html

Direct link to the build log: https://launchpad.net/ubuntu/+archive/test-rebuild-20110816/+build/2695563/+files/buildlog_ubuntu-oneiric-amd64.hardinfo_0.5.1-1.1ubuntu4_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 861 lines into the build log:

gcc -O0 -g -fPIC -pipe -Wall -g -pthread -I/usr/include/gtk-2.0 -I/usr/lib/x86_64-linux-gnu/gtk-2.0/include -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/pango-1.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -pthread -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/libsoup-2.4 -I/usr/include/libxml2 -I. -c fftbench.c -o fftbench.o
make[2]: Leaving directory `/build/buildd/hardinfo-0.5.1'
gcc -O0 -g -fPIC -pipe -Wall -g -pthread -I/usr/include/gtk-2.0 -I/usr/lib/x86_64-linux-gnu/gtk-2.0/include -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/pango-1.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -pthread -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/libsoup-2.4 -I/usr/include/libxml2 -I. -o benchmark.so -shared benchmark.c fbench.o sha1.o blowfish.o md5.o nqueens.o fftbench.o \
   -lpthread -lgthread-2.0 -lrt -pthread -lgtk-x11-2.0 -lgdk-x11-2.0 -latk-1.0 -lgio-2.0 -lpangoft2-1.0 -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lm -lcairo -lpango-1.0 -lfreetype -lfontconfig -lgobject-2.0 -lgmodule-2.0 -lgthread-2.0 -lrt -lglib-2.0
ln -sf ../benchmark.so modules
gcc -g -fPIC -pipe -Wall -g -pthread -I/usr/include/gtk-2.0 -I/usr/lib/x86_64-linux-gnu/gtk-2.0/include -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/pango-1.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -pthread -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/libsoup-2.4 -I/usr/include/libxml2 -I. -o network.so -shared network.c -lpthread -lgthread-2.0 -lrt -pthread -lgtk-x11-2.0 -lgdk-x11-2.0 -latk-1.0 -lgio-2.0 -lpangoft2-1.0 -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lm -lcairo -lpango-1.0 -lfreetype -lfontconfig -lgobject-2.0 -lgmodule-2.0 -lgthread-2.0 -lrt -lglib-2.0
ln -sf ../network.so modules
gcc -g -fPIC -pipe -Wall -g -o hardinfo -Wl,-export-dynamic hardinfo.o shell.o util.o iconcache.o loadgraph.o menu.o stock.o callbacks.o expr.o report.o binreloc.o vendor.o socket.o syncmanager.o -lpthread -lgthread-2.0 -lrt -pthread -lgtk-x11-2.0 -lgdk-x11-2.0 -latk-1.0 -lgio-2.0 -lpangoft2-1.0 -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lm -lcairo -lpango-1.0 -lfreetype -lfontconfig -lgobject-2.0 -lgmodule-2.0 -lgthread-2.0 -lrt -lglib-2.0 \
  -pthread -lsoup-2.4 -lxml2 -lm -lgio-2.0 -lz -lresolv -lgobject-2.0 -lffi -lgmodule-2.0 -ldl -lgthread-2.0 -lglib-2.0 -lrt
/usr/bin/ld: cannot find -lffi
collect2: ld returned 1 exit status
make[1]: *** [all] Error 1
make[1]: Leaving directory `/build/buildd/hardinfo-0.5.1'
make: *** [build-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110821-0617
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/hardinfo-0.5.1