anchor.diff:    #+sbcl      (progn (sb-unix::int-syscall ("setenv" sb-alien:c-string sb-alien:c-string sb-alien:int)
   					   varname newvalue 1)
   		     (getenv varname))
  +  #+gcl       (si:setenv varname newvalue)
     )
   
   #+(or mcl Lispworks)
  
positive.code:   #+lispworks (hcl::getenv varname) 	;?
    #+cmu       (cdr (assoc (intern varname "KEYWORD") ext:*environment-list*))
    #+sbcl      (sb-ext:posix-getenv  varname)
    )
  
  (defun setenv (varname newvalue)
  
negative.code:     #+mcl       (ccl::%chdir          directory)
      #+cmu       (setf (extensions:default-directory) directory)
      #+sbcl      (sb-unix::int-syscall ("chdir" sb-alien:c-string) directory)
      ;#+gcl       
      ;; in Allegro CL, at least,
      ;; if (current-directory) is already a pathname, then
      ;; (make-pathname (current-directory)) will fail
  