Source files here are included in the test file in the parent directory.

You can put the external srfi test source files in this directory.  When
you do so, we recommend to keep changes in these files minimal, so that
it will be easier to incorporate updates from the upstreams.  Many srfi
tests are written in either srfi-64, Chibi test library, or portable
Scheme, and you can put Gauche-specific stuff in the main test file
(test/srfi.scm) that include the original file.
