gzrt version 0.5-1 failed to build on amd64 with GCC-4.6/oneiric

gzrt version 0.5-1 failed to build on amd64 with GCC-4.6/oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2452490

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/2452490/+files/buildlog_ubuntu-natty-amd64.gzrt_0.5-1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 837 lines into the build log:

cc -g -O2 -Wall -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -Wl,-Bsymbolic-functions -lz gzrecover.c -o gzrecover
gzrecover.c: In function 'main':
gzrecover.c:335:21: warning: format '%d' expects argument of type 'int', but argument 3 has type 'size_t' [-Wformat]
/tmp/ccUtGYS9.o: In function `init_zlib':
/build/buildd/gzrt-0.5/gzrecover.c:126: undefined reference to `inflateInit2_'
/tmp/ccUtGYS9.o: In function `main':
/build/buildd/gzrt-0.5/gzrecover.c:253: undefined reference to `inflate'
/build/buildd/gzrt-0.5/gzrecover.c:287: undefined reference to `inflateEnd'
/build/buildd/gzrt-0.5/gzrecover.c:337: undefined reference to `inflateEnd'
/build/buildd/gzrt-0.5/gzrecover.c:277: undefined reference to `inflateEnd'
collect2: ld returned 1 exit status
make[1]: *** [gzrecover] Error 1
make[1]: Leaving directory `/build/buildd/gzrt-0.5'
make: *** [build-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110423-0902
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/gzrt-0.5