glaurung version 2.2-2 failed to build on amd64 with GCC-4.6/oneiric

glaurung version 2.2-2 failed to build on amd64 with GCC-4.6/oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110413/+buildjob/2451167

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/2451167/+files/buildlog_ubuntu-natty-amd64.glaurung_2.2-2_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 871 lines into the build log:

g++ -g -O2 -DNDEBUG -Wall -g -O3 -fno-exceptions -fomit-frame-pointer -fno-rtti -fstrict-aliasing -c -o mersenne.o mersenne.cpp
g++ -g -O2 -DNDEBUG -Wall -g -O3 -fno-exceptions -fomit-frame-pointer -fno-rtti -fstrict-aliasing -c -o book.o book.cpp
g++ -g -O2 -DNDEBUG -Wall -g -O3 -fno-exceptions -fomit-frame-pointer -fno-rtti -fstrict-aliasing -c -o bitbase.o bitbase.cpp
g++ -g -O2 -DNDEBUG -Wall -g -O3 -fno-exceptions -fomit-frame-pointer -fno-rtti -fstrict-aliasing -c -o san.o san.cpp
san.cpp: In function 'const string move_to_san(Position&, Move)':
san.cpp:85:18: warning: variable 'to' set but not used [-Wunused-but-set-variable]
g++ -g -O2 -DNDEBUG -Wall -g -O3 -fno-exceptions -fomit-frame-pointer -fno-rtti -fstrict-aliasing -c -o benchmark.o benchmark.cpp
g++ -Wl,-Bsymbolic-functions -lm -lpthread -o glaurung bitboard.o color.o pawns.o material.o endgame.o evaluate.o main.o misc.o move.o movegen.o history.o movepick.o search.o piece.o position.o square.o direction.o tt.o value.o uci.o ucioption.o mersenne.o book.o bitbase.o san.o benchmark.o
search.o: In function `init_threads()':
/build/buildd/glaurung-2.2/src/search.cpp:516: undefined reference to `pthread_create'
collect2: ld returned 1 exit status
make[1]: *** [glaurung] Error 1
make[1]: Leaving directory `/build/buildd/glaurung-2.2/src'
make: *** [build-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110422-2242
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/glaurung-2.2