I planned to put just the file system routines into these files, but
there are starting to be so many of them that I don't want to
duplicate the same set for networking, subprocesses etc.
R7RS syntax is: (import (library name here))
We translate this into the internal path "library/name/here". This will allow
us to easily load libraries from files later on by appending the ".sld" file
name extension.