>  As I remarked above, `define/m` and `return/m` are auxiliary syntax
of `do/m`, so I believe they should not be exported.

Auxiliary syntax is handled by the module system: for example, `(scheme
base)` exports `=>`, `else`, and `...` as identifiers. This is because
syntax-rules should match those identifiers hygienically (some macro
expanders don't do this).

-- Peter McGoron