S9 LIB  (vector-map! procedure^1 vector)  ==>  unspecific

        (load-from-library "vector-mapb.scm")

Destructively map a procedure over a vector, changing each member
of the vector to the value of the procedure call.

(let ((v (vector 1 2 3)))
  (vector-map! - v)
  v)                       ==>  #(-1 -2 -3)
