Notes on the Edwin sources:

If you want to add a new file to the source tree, you need to 
modify the following three files:

	decls.scm
	ed-ffi.scm
	edwin.pkg

If the file should be loaded into the default edwin band, you must also
edit the file:

	edwin.ldr

If the file is to be autoloaded, you must edit the file:

	loadef.scm

So, in either case, you have to change four files in /scheme/src/edwin.
Of course, you also have to put a copy of your file in
/scheme/src/edwin, too, and you have to put links to new-file.scm in
/scheme/300/edwin and /scheme/800/edwin.