Refactoring: Slightly simplify the logic for handling the return value of a macro.
This moves: if (unev == Unbound) { assign(unev, NIL); }
To the branch where this change matters.
It also precomputes its effect instead of assigning env twice.
Note that I haven't confirmed that unev can be Unbound.
Authored by: david_costanzo 2026-07-06
Parent: [r6343]
Child: [r6345]
