mush version 7.2.5unoff2-25.1ubuntu1 failed to build in oneiric

mush version 7.2.5unoff2-25.1ubuntu1 failed to build in oneiric
Link to failed build: https://launchpad.net/ubuntu/+archive/test-rebuild-20110816/+build/2705831

Details about the rebuild:
http://people.ubuntuwire.org/~wgrant/rebuild-ftbfs-test/test-rebuild-20110816-oneiric.html

Direct link to the build log: https://launchpad.net/ubuntu/+archive/test-rebuild-20110816/+build/2705831/+files/buildlog_ubuntu-oneiric-i386.mush_7.2.5unoff2-25.1ubuntu1_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Source-dependencies not satisfied'.
Excerpt 218 lines into the build log:

Checking for source dependency conflicts...
  /usr/bin/sudo /usr/bin/apt-get --purge $CHROOT_OPTIONS -q -y install libncurses5-dev libreadline5-dev debhelper
Reading package lists...
Building dependency tree...
Reading state information...
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libreadline5-dev : Depends: libreadline5 (= 5.2-7build1) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
apt-get failed.
Package installation failed
Trying to reinstall removed packages:
Trying to uninstall newly installed packages:
Source-dependencies not satisfied; skipping mush