Don't clean away headers generated by Configure

        }

    }

    ### Add information about files generated by Configure

    foreach (map { abs2rel($_) } @generated_headers) {

        die "Configure gerenerated header file $_ has a GENERATE in a build.info\n"

            if $unified_info{generate}->{$_};

        $unified_info{generate}->{$_} = "Generated by Configure";

    }

    ### Make unified_info a bit more efficient

    # One level structures

    foreach (("programs", "libraries", "engines", "scripts", "extra", "overrides")) {