How to have one catkin workspace rely on another

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Is there a generally accepted way to handle the case where I have some libraries that are generated in one catkin workspace and are used by a project in another catkin workspace?

What I mean by handle is, how do I tell the project workspace where to find the libraries generated by the library workspace?

I can imagine lots of ways to do this using symbolic links and/or environment variables but they all seem somewhat fragile or messy. I'm wondering if anyone has a way of doing this that they like.