In https://precice.org/installation-source-installation.html, we describe how to set the PKG_CONFIG_PATH for an installed copy of preCICE.

precice/precice#1238 added a new libprecice.pc file directly in the build/ directory, as described in precice/precice#1238 (comment).

This would generally be useful also for users that just want to use preCICE without installing it to another path. In any case, we should document it.

However, I think we should now look at the bigger picture of how we introduce this option to the user. Just editing this page to add a hint is not enough, in my opinion.