latex2rtf version 1.9.19-4.1 failed to build on amd64 with GCC-4.6/oneiric

latex2rtf version 1.9.19-4.1 failed to build on amd64 with GCC-4.6/oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2456035

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/2456035/+files/buildlog_ubuntu-natty-amd64.latex2rtf_1.9.19-4.1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 400 lines into the build log:

preparse.c:199:29: warning: variable 'text' set but not used [-Wunused-but-set-variable]
gcc -O2 -Wall -DUNIX -DHAS_STRDUP -g -O2 -c -o vertical.o vertical.c
vertical.c: In function 'CmdVspace':
vertical.c:353:15: warning: 'vspace' may be used uninitialized in this function [-Wuninitialized]
gcc -O2 -Wall -DUNIX -DHAS_STRDUP -g -O2 -lm fonts.o direct.o encodings.o commands.o stack.o funct1.o tables.o chars.o ignore.o cfg.o main.o utils.o parser.o lengths.o counters.o preamble.o letterformat.o equations.o convert.o xrefs.o definitions.o graphics.o mygetopt.o styles.o preparse.o vertical.o -o latex2rtf
chars.o: In function `putOverstrikeChar':
/build/buildd/latex2rtf-1.9.19/chars.c:145: undefined reference to `floor'
utils.o: In function `my_rint':
/build/buildd/latex2rtf-1.9.19/utils.c:55: undefined reference to `floor'
/build/buildd/latex2rtf-1.9.19/utils.c:56: undefined reference to `ceil'
collect2: ld returned 1 exit status
make[1]: *** [latex2rtf] Error 1
make[1]: Leaving directory `/build/buildd/latex2rtf-1.9.19'
make: *** [build-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110424-0005
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/latex2rtf-1.9.19