Specify an entire directory tree for string imports

[Alex Parrill via Digitalmars-d-learn]

I have a directory structure like this:

        .
        |   test.d
        |
        \---test
            |   test1.txt
            |
            \---subfolder
                    test2.txt
I am running test.d using this command:

        rdmd -Jtest test.d

I can do `import("test1.txt")` from test.d successfully, however, 
`import("subfolder/test2.txt")` fails with the error `file 
"subfolder/test2.txt" cannot be found or not in a path specified 
with -J`

I'm guessing that the -J option doesn't operate recursively, and 
that I'm not allowed to import files from `test/subfolder`.

Is there a way to make the entire `test` directory tree available 
for string imports?