replace sc-expand with sc-expand3, removing binding for sc-expand3

* module/ice-9/boot-9.scm (sc-expand3):
* module/ice-9/psyntax.scm (sc-expand3): Replace sc-expand with
  sc-expand3, as expand3 with one argument is the same as sc-expand.

* module/ice-9/psyntax-pp.scm: Regenerated.

* module/ice-9/compile-psyntax.scm:
* module/language/scheme/compile-ghil.scm: Change callers to sc-expand3
  to use sc-expand.

module/ice-9/boot-9.scm

@@ -215,7 +215,6 @@
 (define bound-identifier=? #f)
 (define free-identifier=? #f)
 (define sc-expand #f)
-(define sc-expand3 #f)
 
 ;; $sc-expand is an implementation detail of psyntax. It is used by
 ;; expanded macros, to dispatch an input against a set of patterns.

module/ice-9/compile-psyntax.scm

@@ -11,7 +11,7 @@
             (close-port out)
             (close-port in))
           (begin
-            (write (sc-expand3 x 'c '(compile load eval))
+            (write (sc-expand x 'c '(compile load eval))
                    out)
             (newline out)
             (loop (read in))))))

module/ice-9/psyntax.scm

@@ -1976,14 +1976,6 @@
 ;;; expanded, and the expanded definitions are also residualized into
 ;;; the object file if we are compiling a file.
 (set! sc-expand
-  (let ((m 'e) (esew '(eval)))
-    (lambda (x)
-      (if (and (pair? x) (equal? (car x) noexpand))
-          (cadr x)
-          (chi-top x null-env top-wrap m esew
-                   (cons 'hygiene (module-name (current-module))))))))
-
-(set! sc-expand3
   (let ((m 'e) (esew '(eval)))
     (lambda (x . rest)
       (if (and (pair? x) (equal? (car x) noexpand))

module/language/scheme/compile-ghil.scm

@@ -69,7 +69,7 @@
      (and=> (cenv-module e) set-current-module)
      (call-with-ghil-environment (cenv-ghil-env e) '()
        (lambda (env vars)
-         (let ((x (sc-expand3 x 'c '(compile load eval))))
+         (let ((x (sc-expand x 'c '(compile load eval))))
            (let ((x (make-ghil-lambda env #f vars #f '()
                                       (translate-1 env #f x)))
                  (cenv (make-cenv (current-module)