epMakefile :: FilePath -> DynFlags -> DynFlags
setDepMakefile f d = d { depMakefile = deOptDep f }

se
setDepMakefile :: FilePath -> DynFlags -> DynFlags
setDepMakefile f d = d { depMakefile = deOptDep f }
setDepMakefile f d = d { depMakefile = deOptDep f }