Issue: REMF-DESTRUCTION-UNSPECIFIED (Version 4)

[Jon L White <jonl@lucid.com>]

re: I'll add that I still prefer the proposal I outlined (awkwardly) in
    November 1987, which was neither explicitly-vague or explicitly-defined.
    The "sequence" functions:
      NREVERSE DELETE DELETE-IF DELETE-IF-NOT DELETE-DUPLICATES NSUBSTITUTE
      NSUBSTITUTE-IF NSUBSTITUTE-IF-NOT
    and the destructive set manipulation functions:
      NUNION NINTERSECTION NSET-EXCLUSIVE-OR
    should be explicitly-vague, but the others 
      SETF of GETF, REMF, SETF of GET, REMPROP, NCONC, NRECONC, NBUTLAST,
      NSUBST, NSUBST-IF, NSUBST-IF-NOT
    should be specified.

I think I prefer your version too, for essentially the reasons you
elucidated further in your msg.

-- JonL --