Pretty printer ignores STREAM-LINE-LENGTH when *PRINT-RIGHT-MARGIN* is bound to NIL

[Levente Mészáros]

CL-USER> *standard-output*
#<SWANK-BACKEND::SLIME-OUTPUT-STREAM {1006AC6A51}>

CL-USER> (defmethod stream-line-length ((s swank-backend::slime-output-stream))
  200)

STYLE-WARNING: redefining STREAM-LINE-LENGTH (#<STANDARD-CLASS SWANK-BACKEND::SLIME-OUTPUT-STREAM>) in DEFMETHOD
#<STANDARD-METHOD STREAM-LINE-LENGTH (SWANK-BACKEND::SLIME-OUTPUT-STREAM) {1006C0DDC1}>

CL-USER> (values *print-pretty* *print-length* *print-right-margin* *print-lines*)
T
NIL
NIL
NIL

CL-USER> (format *standard-output* "~<~A~>" (loop repeat 20 collect "foo ")) ; wraps at around 75
(foo foo foo foo foo foo foo foo foo foo foo foo foo foo foo
 foo foo foo foo foo )
NIL

;; the line-length slot in the pretty-stream structure initializes
;; (line-length (or *print-right-margin*
;; (setf cl-user::a (sb!impl::line-length (setf cl-user::s target)))
;; default-line-length)
;; :type column)
;;
;; but the call to sb-impl::line-length is made on an *intermediate* string-output-stream
;; therefore it ignores the line length customization
;;
;; there might be other similar problems like this one due to the wrapped stream