Reading package lists... Done Building dependency tree Reading state information... Done 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: libpq-dev : Depends: libkrb5-dev but it is not going to be installed Depends: comerr-dev but it is not going to be installed E: Unable to correct problems, you have held broken packages.
You could try install it from source code. For libpq-dev, you must install PostgreSQL
That link show you how to install: