[Haskell-cafe] Cabal: updating environment variable in a dependency

Hi all, I have two separate packages, a library and an app. In the library's Setup.hs I set the LIBRARY_PATH environment variable to a place where I install a custom C shared library, but when the app is built LIBRARY_PATH is empty. I realize that GHC can build and link C code but for the purposes of this project that wasn't workable. So is there a way to make this environment variable hack work or, even better, a good way a dependency can pass custom information to its dependents? Thanks! -deech