bbtime version 0.1.5-12 failed to build on i386

bbtime version 0.1.5-12 failed to build on i386
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2446218

Direct link to the build log: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2446218/+files/buildlog_ubuntu-natty-i386.bbtime_0.1.5-12_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 1348 lines into the build log:

/build/buildd/bbtime-0.1.5/Basemenu.cc:804: undefined reference to `XUngrabPointer'
Basemenu.o: In function `Basemenu::Reconfigure()':
/build/buildd/bbtime-0.1.5/Basemenu.cc:819: undefined reference to `XSetWindowBackground'
/build/buildd/bbtime-0.1.5/Basemenu.cc:820: undefined reference to `XSetWindowBorder'
Basemenu.o: In function `Basemenu::buttonReleaseEvent(XButtonEvent*)':
/build/buildd/bbtime-0.1.5/Basemenu.cc:617: undefined reference to `XUngrabPointer'
timemenu.o: In function `Timemenu::Show()':
/build/buildd/bbtime-0.1.5/timemenu.cc:161: undefined reference to `XRaiseWindow'
collect2: ld returned 1 exit status
make[2]: *** [bbtime] Error 1
make[2]: Leaving directory `/build/buildd/bbtime-0.1.5'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/build/buildd/bbtime-0.1.5'
make: *** [build-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110419-0311
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/bbtime-0.1.5