libfann version 2.1.0~beta~dfsg-2build1 failed to build on amd64 with GCC-4.6/oneiric

libfann version 2.1.0~beta~dfsg-2build1 failed to build on amd64 with GCC-4.6/oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2457495

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/2457495/+files/buildlog_ubuntu-natty-amd64.libfann_2.1.0%7Ebeta%7Edfsg-2build1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 962 lines into the build log:

pyfann/pyfann_wrap.cxx:4183:3: error: 'ptrdiff_t' was not declared in this scope
pyfann/pyfann_wrap.cxx:4183:3: note: suggested alternatives:
/usr/include/c++/4.6/x86_64-linux-gnu/bits/c++config.h:156:28: note: 'std::ptrdiff_t'
/usr/include/c++/4.6/x86_64-linux-gnu/bits/c++config.h:156:28: note: 'std::ptrdiff_t'
pyfann/pyfann_wrap.cxx:4183:13: error: expected ';' before 'result'
pyfann/pyfann_wrap.cxx:4199:3: error: 'result' was not declared in this scope
pyfann/pyfann_wrap.cxx:4199:59: error: 'const struct swig::SwigPyIterator' has no member named 'operator-'
pyfann/pyfann_wrap.cxx:4200:48: error: expected type-specifier before 'ptrdiff_t'
pyfann/pyfann_wrap.cxx:4200:48: error: expected '>' before 'ptrdiff_t'
pyfann/pyfann_wrap.cxx:4200:48: error: expected '(' before 'ptrdiff_t'
error: command 'gcc' failed with exit status 1
make[1]: *** [override_dh_auto_build] Error 1
make[1]: Leaving directory `/build/buildd/libfann-2.1.0~beta~dfsg'
make: *** [build] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110424-0243
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/libfann-2.1.0~beta~dfsg