Installing library in specific location on Mac and using it later

I'm interested in being able to call `runhaskell` exposing specific libraries, from any directory, and without having a `cabal.project` or `package.env` in the current directory. I can pass any arguments or environment variables I want to `runhaskell`, and I should place all files in a specific location (call it `/myLibraryDir`), not in the user's home.

What is the way of installing a library with Cabal so that all files and libraries are installed in under specific path, and can later be found?

I'm looking for the arguments to:

`cabal myLibrary`

such that later I can run from any directory:

`runhaskell <<< 'import MyModule; main = putStrLn "Success"'`

Start by tracing the Cabal installation command and runhaskell package-discovery paths described in the issue, including how cabal.project and package.env are consulted. Done should be a documented or implemented way to place the library under /myLibraryDir and import it with runhaskell from any directory without those files.

Written by the indexing model from the issue text.