libaio version 0.3.109-1ubuntu1 failed to build in oneiric

libaio version 0.3.109-1ubuntu1 failed to build in oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110816/+build/2699110

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/2699110/+files/buildlog_ubuntu-oneiric-i386.libaio_0.3.109-1ubuntu1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 568 lines into the build log:

cc -Wall -Werror -I../src -g -O -DTEST_NAME=\"cases/6.t\" -o cases/6.p main.c ../src/libaio.a
cc -Wall -Werror -I../src -g -O -DTEST_NAME=\"cases/7.t\" -o cases/7.p main.c ../src/libaio.a
cc -Wall -Werror -I../src -g -O -DTEST_NAME=\"cases/11.t\" -o cases/11.p main.c ../src/libaio.a
cc -Wall -Werror -I../src -g -O -DTEST_NAME=\"cases/12.t\" -o cases/12.p main.c ../src/libaio.a
In file included from main.c:34:0:
cases/12.t: In function 'test_main':
cases/12.t:21:6: error: variable 'res' set but not used [-Werror=unused-but-set-variable]
cc1: all warnings being treated as errors

make[2]: *** [cases/12.p] Error 1
make[2]: Leaving directory `/build/buildd/libaio-0.3.109/harness'
make[1]: *** [partcheck] Error 2
make[1]: Leaving directory `/build/buildd/libaio-0.3.109'
make: *** [check-arch] Error 2
dpkg-buildpackage: error: /usr/bin/fakeroot debian/rules binary gave error exit status 2
******************************************************************************
Build finished at 20110817-1250
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/libaio-0.3.109