qwt version 6.0.0-1 failed to build in oneiric

qwt version 6.0.0-1 failed to build in oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110816/+build/2710017

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/2710017/+files/buildlog_ubuntu-oneiric-i386.qwt_6.0.0-1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 716 lines into the build log:

ln -f -s "libqwtmathml.so.6.0.0" "/build/buildd/qwt-6.0.0/debian/tmp/usr/lib/libqwtmathml.so.6"
ln -f -s "libqwtmathml.so.6.0.0" "/build/buildd/qwt-6.0.0/debian/tmp/usr/lib/libqwtmathml.so.6.0"
make[3]: Leaving directory `/build/buildd/qwt-6.0.0/textengines/mathml'
make[2]: Leaving directory `/build/buildd/qwt-6.0.0/textengines'
cd designer/ && make -f Makefile install
make[2]: Entering directory `/build/buildd/qwt-6.0.0/designer'
install -m 755 -p "plugins/designer/libqwt_designer_plugin.so" "/build/buildd/qwt-6.0.0/debian/tmp/usr/lib/i386-linux-gnu/qt4/plugins/designer/libqwt_designer_plugin.so"
: --strip-unneeded "/build/buildd/qwt-6.0.0/debian/tmp/usr/lib/i386-linux-gnu/qt4/plugins/designer/libqwt_designer_plugin.so"
make[2]: Leaving directory `/build/buildd/qwt-6.0.0/designer'
make[1]: Leaving directory `/build/buildd/qwt-6.0.0'
   dh_install -O--parallel -O--list-missing
cp: cannot stat `debian/tmp/usr/lib/qt4/plugins/designer/libqwt_designer_plugin.so': No such file or directory
dh_install: cp -a debian/tmp/usr/lib/qt4/plugins/designer/libqwt_designer_plugin.so debian/libqwt-dev//usr/lib/qt4/plugins/designer/ returned exit code 1
make: *** [binary] Error 2
dpkg-buildpackage: error: /usr/bin/fakeroot debian/rules binary gave error exit status 2
******************************************************************************
Build finished at 20110818-1331
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/qwt-6.0.0