Try libreadline5 or libreadline4 (you might need -dev too).
apt-get install libreadline5 libreadline5-dev
Carl
P.S. You might want to try this out:
https://openacs.org/wiki/Installing%20OpenACS%20on%20Debian%20Linux
Much less painful (e.g. apt-get install postgresql
will install the right version of readline for you)