Actually, once you move the prologue-code, epilogue-code, etc., to the system definition where it belongs (possibly a secondary system), then nothing should be in the operation, and make-build becomes non-sensical. Just use asdf:make on the system that has the suitable build-operation.
Just because make-build is documented in the ECL manual doesn't make it sensical. It needs to be deleted, and the ECL manual amended.
—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org You think minimum height restrictions make children taller? — Luke McCormick, regarding minimum wage restrictions