Simpler way to check an _optional_ meta attribute for a possible value...

In my derive_builder clone, here is what I need to do to see whether the user has set #[builder(pattern="owned")]:

    ${defcond T_OWN all(tmeta(builder(pattern)),
                        approx_equal(${tmeta(builder(pattern)) as str}, "owned"))
    }

I had hoped instead to say something like:

   ${defcond T_OWN approx_equal(${tmeta(builder(pattern)) missing_ok as str }, "owned"}

Or maybe even:

   ${defcond T_OWN approx_equal(${tmeta(builder(pattern)) default "mutable" as str }, "owned"}