mercurial-buildpackage: FTBFS: ./Script.hx:61: characters 1-34 : Class not found : neko.io.FileOutput

Imported from Debian bug http://bugs.debian.org/719405:

Source: mercurial-buildpackage
Version: 0.10
Severity: serious
Tags: jessie sid
User: <email address hidden>
Usertags: qa-ftbfs-20130811 qa-ftbfs
Justification: FTBFS on amd64

Hi,

During a rebuild of all packages in sid, your package failed to build on
amd64.

Relevant part (hopefully):
> debian/rules build
> dh_testdir
> /usr/bin/make VENDOR_VERSION="Debian"
> make[1]: Entering directory `/«PKGBUILDDIR»'
> sed -e 's/@VENDOR@/'"Debian"'/g' <Constants.hx.in >Constants.hx
> haxe -neko mercurial-buildpackage.n -cmd 'nekotools boot mercurial-buildpackage.n' -main MercurialBuildPackage
> ./Script.hx:61: characters 1-34 : Class not found : neko.io.FileOutput
> make[1]: *** [mercurial-buildpackage] Error 1

The full build log is available from:
   http://aws-logs.debian.net/ftbfs-logs/2013/08/11/mercurial-buildpackage_0.10_unstable.log

A list of current common problems and possible solutions is available at
http://wiki.debian.org/qa.debian.org/FTBFS . You're welcome to contribute!

About the archive rebuild: The rebuild was done on EC2 VM instances from
Amazon Web Services, using a clean, minimal and up-to-date chroot. Every
failed build was retried once to eliminate random failures.