qc-usb version 0.6.6-7 failed to build on amd64 with GCC-4.6/oneiric

qc-usb version 0.6.6-7 failed to build on amd64 with GCC-4.6/oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2466662

Details about the rebuild:
https://lists.ubuntu.com/archives/ubuntu-devel/2011-April/033042.html

Direct link to the build log: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2466662/+files/buildlog_ubuntu-natty-amd64.qc-usb_0.6.6-7_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 392 lines into the build log:

cc -Wall -g -O2 -Wl,-z,defs -o qcset -lm qcset.c
qcset.c: In function 'main':
qcset.c:708:9: warning: format not a string literal and no format arguments [-Wformat-security]
/tmp/ccVd5CFD.o: In function `main':
/build/buildd/qc-usb-0.6.6/qcset.c:646: undefined reference to `pow'
/build/buildd/qc-usb-0.6.6/qcset.c:646: undefined reference to `pow'
/build/buildd/qc-usb-0.6.6/qcset.c:647: undefined reference to `pow'
/build/buildd/qc-usb-0.6.6/qcset.c:647: undefined reference to `pow'
/build/buildd/qc-usb-0.6.6/qcset.c:647: undefined reference to `pow'
/tmp/ccVd5CFD.o:/build/buildd/qc-usb-0.6.6/qcset.c:648: more undefined references to `pow' follow
collect2: ld returned 1 exit status
make[1]: *** [qcset] Error 1
make[1]: Leaving directory `/build/buildd/qc-usb-0.6.6'
make: *** [build-arch-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110425-2214
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/qc-usb-0.6.6