Consolidate TRILINOS_UNUSED_FUNCTION macro definition in Teuchos
Created by: mhoemmen
According to @bmpersc (see Issue #83 (closed)), the logic for defining TRILINOS_UNUSED_FUNCTION appears twice in Tpetra and once in Teuchos. Since Tpetra depends on Teuchos, it would make sense to consolidate this logic in Teuchos. An alternate approach would be for each package to define its own ${PACKAGE}_UNUSED_FUNCTION macro. Either way, we shouldn't try to define the same thing three times. It's not causing build errors but it's error-prone.