Quantifiers like SOME and EVERY are implemented in terms of (MAP NIL)
of a wrapper function with early RETURN. If type information does not
enable MAP to be open coded, declarations are necessary to avoid
consing up a closure and a value cell for the return.
DX functions really shouldn't cause value cells for return blocks.
Also, revert d0f65b07a30adc989e36a82ddc0ed54d135d638e which is
now mostly redundant.