* module/language/tree-il/analyze.scm (<binding-info>): New record type.
(report-unused-variables): New procedure.
* module/language/tree-il/compile-glil.scm (%warning-passes): New
variable.
(compile-glil): Honor `#:warnings' from OPTS.
* test-suite/tests/tree-il.test (call-with-warnings): New procedure.
(%opts-w-unused): New variable.
("warnings"): New test prefix.