An example using the C preprocessor
===================================

file: tests/cpp/executable.hs
    main = if DATA then putStrLn "It works." else putStrLn "Ooops."

Here's the ``Setup.hs`` file.

file: tests/cpp/Setup.hs
    import Distribution.Franchise
    
    configure = do defineAs "DATA" "True"
                   ghcFlags ["-cpp"]
    
    main = build [] configure
           (executable "executable" "executable.hs" [])

And finally we'll test that this executable actually builds and runs.

file: tests/cpp/cpp.sh
....set -ev
    runghc Setup.hs build
...../executable
    ./executable | grep works