Is there an easy way to declare a particular directory as a location for finding Haskell modules, similar to PYTHONPATH and similar environment variables for other languages? The GHC_PACKAGE_PATH doesn't seem to be quite the same thing. There's the option of setting -iSOMEPATH in one's .ghci file, but that doesn't seem to allow declaring a relative path via ~ or $HOME, making it a bit of a pain to maintain separate versions of one's .ghci across different machines.