psignifit version 2.5.6-3 failed to build on amd64 with GCC-4.6/oneiric

psignifit version 2.5.6-3 failed to build on amd64 with GCC-4.6/oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2465753

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/2465753/+files/buildlog_ubuntu-natty-amd64.psignifit_2.5.6-3_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 439 lines into the build log:

/build/buildd/psignifit-2.5.6/psig-src/supportfunctions.c:548: undefined reference to `log'
supportfunctions.o: In function `xlogy_j':
/build/buildd/psignifit-2.5.6/psig-src/supportfunctions.c:561: undefined reference to `log'
supportfunctions.o: In function `CheckValue':
/build/buildd/psignifit-2.5.6/psig-src/supportfunctions.c:569: undefined reference to `floor'
supportfunctions.o: In function `CorrelationCoefficient':
/build/buildd/psignifit-2.5.6/psig-src/supportfunctions.c:603: undefined reference to `sqrt'
supportfunctions.o: In function `median':
/build/buildd/psignifit-2.5.6/psig-src/supportfunctions.c:832: undefined reference to `floor'
/build/buildd/psignifit-2.5.6/psig-src/supportfunctions.c:832: undefined reference to `ceil'
collect2: ld returned 1 exit status
make[1]: *** [psignifit] Error 1
make[1]: Leaving directory `/build/buildd/psignifit-2.5.6/psig-src'
make: *** [build-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110425-1753
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/psignifit-2.5.6