* test-suite/tests/srfi-18.test: Enclose the tests in a begin instead of
an and. Before, they were not being run, for some reason I don't
fully understand.
* module/language/tree-il/compile-glil.scm (flatten): For applications in
"drop" context, allow the procedure to return unspecified values
(including 0 values).
* test-suite/tests/tree-il.test ("application"): Adapt test.
* module/srfi/srfi-18.scm (wrap): Clarify.
* test-suite/tests/srfi-18.test: Fix so that the expression importing
srfi-18 is expanded before the tests. However the tests are still
failing, something about 0-valued returns...
