Some option parsing progress, and make failure

- Move files into an `Rcm` directory instead of `src`.
- Re-write the unix `getopt(3)` function because that doesn't seem to
  exist already.
- Implement the very basics of a command-line tool: parse some
  arguments.
- Can no longer build the program using `make lsrc`. Seems like it
  cannot find `System.FilePath` when I try.