Steel Bank Common Lisp

Hello,
dummy question (sorry ;-))
I am reading the Erann Gat's tutorial about the packages:
http://www.flownet.com/ron/packages.pdf
It is written:
--------------------------8<--------------------------------------
? (trace make-symbol)
NIL
? 'foobaz
Calling (MAKE-SYMBOL "FOOBAZ")
MAKE-SYMBOL returned #:FOOBAZ
FOOBAZ
The reader apparently makes symbols the same way we did, by calling
MAKE-SYMBOL. 
But wait, the symbol returned by MAKE-SYMBOL had that funny #: in front
of it, but by the time the reader was done the #: prefix had wanished.
--------------------------8<--------------------------------------

On my Sid Debian box I use clisp or sbcl and both give:

With clisp:
==========
(trace make-symbol)
** - Continuable Error
TRACE(MAKE-SYMBOL): #<PACKAGE COMMON-LISP> is locked
Si vous continuez (en tapant «continue»): Ignore the lock and proceed
The following restarts are also available:
ABORT          :R1      Abort main loop
Break 1 [2]> continue
WARNING: TRACE: redefining fonction MAKE-SYMBOL in top-level, was defined in C
;; Tracing function MAKE-SYMBOL
(MAKE-SYMBOL)
[3]> 'foobaz
FOOBAZ
[4]> 

With sbcl:
=========
* (trace make-symbol)

(MAKE-SYMBOL)
* 'foobaz

FOOBAZ
* 

My question:
How the reader makes symbols with clisp and sbcl which I use ?


-- 
Gérard