haxe version 1:2.5-1 failed to build on i386

haxe version 1:2.5-1 failed to build on i386
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110329/+buildjob/2395498

Direct link to the build log: https://launchpad.net/ubuntu/+archive/test-rebuild-20110329/+buildjob/2395498/+files/buildlog_ubuntu-natty-i386.haxe_1%3A2.5-1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 1009 lines into the build log:

 dpkg-source --before-build haxe-2.5
dpkg-buildpackage: host architecture i386
 /usr/bin/fakeroot debian/rules clean
dh_testdir
dh_testroot
rm -f *-stamp
rm -rf /build/buildd/haxe-2.5/bin
rm -f /build/buildd/haxe-2.5/haxe/lexer.ml
rm -f /build/buildd/haxe-2.5/ocaml/xml-light/xml_parser.ml
rm -f /build/buildd/haxe-2.5/ocaml/xml-light/xml_parser.mli
rm -f /build/buildd/haxe-2.5/ocaml/xml-light/xml_lexer.ml
find /build/buildd/haxe-2.5 -name '*.o' -o -name '*.cmi' -o -name '*.cmx' -o -name '*.cmo' \
  -o -name '*.cma' -o -name '*.a' -o -name '*.cmxa' -o -name '*.n' \
  | xargs rm -rf
rm -f /build/buildd/haxe-2.5/haxedoc
rm -f /build/buildd/haxe-2.5/haxelib
dh_clean
 debian/rules build
dh_testdir
ocaml debian/install_native.ml
Exception:
Failure
 "LibZ was not found on your system, please install it or modify the search directories in the install script".
make: *** [build-stamp] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
******************************************************************************
Build finished at 20110403-0922
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/haxe-2.5