packeth version 1.6.5-1 failed to build on amd64 with GCC-4.6/oneiric

packeth version 1.6.5-1 failed to build on amd64 with GCC-4.6/oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2464325

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/2464325/+files/buildlog_ubuntu-natty-amd64.packeth_1.6.5-1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 15262 lines into the build log:

/build/buildd/packeth-1.6.5/src/savepacket.c:235: undefined reference to `g_type_check_instance_cast'
/build/buildd/packeth-1.6.5/src/savepacket.c:235: undefined reference to `gtk_entry_get_text'
/build/buildd/packeth-1.6.5/src/savepacket.c:251: undefined reference to `g_type_check_instance_cast'
/build/buildd/packeth-1.6.5/src/savepacket.c:252: undefined reference to `g_type_check_instance_cast'
/build/buildd/packeth-1.6.5/src/savepacket.c:252: undefined reference to `gtk_entry_get_text'
/build/buildd/packeth-1.6.5/src/savepacket.c:268: undefined reference to `g_type_check_instance_cast'
/build/buildd/packeth-1.6.5/src/savepacket.c:269: undefined reference to `g_type_check_instance_cast'
collect2: ld returned 1 exit status
make[2]: *** [packETH] Error 1
make[2]: Leaving directory `/build/buildd/packeth-1.6.5'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/build/buildd/packeth-1.6.5'
dh_auto_build: make -j1 returned exit code 2
make: *** [build] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110425-0922
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/packeth-1.6.5