Projucer Environment Variables

Is there any way to get the jucer project directory as an environment variable?

For example, I have external libraries that I’d like to include in my project folder, but I’d rather not set the library include paths as absolute paths on my machine since the project may be shared between developers. I’d like to do something like this in the jucer:

Extra Library Search Paths -> 

Or something like that. I searched around the manual/forum and couldn’t seem to find anything that fits the bill.

The Projucer’s path settings will be relative to the project file so you could do something like ../../extern/ if you folder structure looks like projectDirectory/Builds/MacOSX.