Some way to check whether a $fmeta/$vmeta is set on _any_ field or variant
Right now, if I want to check whether builder(sub_builder)
is set on any field, I have to do this:
${defcond T_ANY_SUB_BUILDER not(approx_equal(
{ ${for fields { ${if fmeta(builder(sub_builder)) {yes}}}} },
{}
))}
This isn't so bad, but while we're thinking of new things to add, this might be one.