Usage of "PURE" strings

[JONL at MIT-MC (Jon L White)]

A number of bugs have arisen from trying to PURCOPY string
(either in NILAID, NIL, or in a lisp with only the STRING
package) - here's another to beware of:
   If you call PURIFY with first argument signaling a general
   clean-up and purification, then the system knows enough to
   close out any remaing pure consing areas *** except for the
   pure string areas.  You must close this out "by hand", by
   doing (SETQ STR/:NO/.PWDSF 0).  Remember that some "dumpers"
   will implicitly call PURIFY thusly;  PURE-SUSPEND is one.