gnote version 0.7.1-1.1ubuntu1build1 failed to build on amd64 with GCC-4.6/oneiric

gnote version 0.7.1-1.1ubuntu1build1 failed to build on amd64 with GCC-4.6/oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2451643

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/2451643/+files/buildlog_ubuntu-natty-amd64.gnote_0.7.1-1.1ubuntu1build1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 2142 lines into the build log:

checking boost/lexical_cast.hpp presence... yes
checking for boost/lexical_cast.hpp... yes
checking for the toolset name used by Boost for g++... configure: WARNING: could not figure out which toolset name to use for g++

checking boost/system/error_code.hpp usability... yes
checking boost/system/error_code.hpp presence... yes
checking for boost/system/error_code.hpp... yes
checking for the Boost system library... yes
checking boost/filesystem/path.hpp usability... yes
checking boost/filesystem/path.hpp presence... yes
checking for boost/filesystem/path.hpp... yes
checking for the Boost filesystem library... no
configure: error: Could not find the flags to link with Boost filesystem
make: *** [debian/stamp-autotools] Error 1
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110423-0335
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/gnote-0.7.1