No need for cl when compiling.

Require eshell, for eshell-defgroup.
(eshell-load-defgroups): Remove.
Require esh-groups rather than loading it.

lisp/eshell/esh-module.el

 ;;; esh-module.el --- Eshell modules
 
-;; Copyright (C) 1999, 2000, 2002, 2003, 2004,
-;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+;; Copyright (C) 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007,
+;;   2008  Free Software Foundation, Inc.
 
 ;; Author: John Wiegley <johnw@gnu.org>
 ;; Keywords: processes
@@ -25,10 +25,7 @@
 
 (provide 'esh-module)
 
-(eval-when-compile
-  (require 'cl)
-  (require 'esh-util))
-
+(require 'eshell)
 (require 'esh-util)
 
 (defgroup eshell-module nil
@@ -38,63 +35,10 @@ customizing the variable `eshell-modules-list'."
   :tag "Extension modules"
   :group 'eshell)
 
-(eval-and-compile
-(defun eshell-load-defgroups (&optional directory)
-  "Load `defgroup' statements from Eshell's module files."
-  (let ((vc-handled-backends nil)) ; avoid VC fucking things up
-    (with-current-buffer
-	(find-file-noselect (expand-file-name "esh-groups.el" directory))
-      (erase-buffer)
-      (insert ";;; do not modify this file; it is auto-generated -*- no-byte-compile: t -*-\n\n")
-      (let ((files (directory-files (or directory
-					(car command-line-args-left))
-				    nil "\\`em-.*\\.el\\'")))
-	(while files
-	  (message "Loading defgroup from `%s'" (car files))
-	  (let (defgroup)
-	    (catch 'handled
-	      (with-current-buffer (find-file-noselect (car files))
-		(goto-char (point-min))
-		(while t
-		  (forward-sexp)
-		  (if (eobp) (throw 'handled t))
-		  (backward-sexp)
-		  (let ((begin (point))
-			(defg (looking-at "(defgroup")))
-		    (forward-sexp)
-		    (if defg
-			(setq defgroup (buffer-substring begin (point))))))))
-	    (if defgroup
-		(insert defgroup "\n\n")))
-	  (setq files (cdr files))))
-      ;; Don't make backups, to avoid prompting the user if there are
-      ;; excess backup versions.
-      (save-buffer 0)))))
-
 ;; load the defgroup's for the standard extension modules, so that
 ;; documentation can be provided when the user customize's
 ;; `eshell-modules-list'.
-(eval-when-compile
-  (when (and (boundp 'byte-compile-current-file)
-	     byte-compile-current-file
-	     (or
-	      (equal (file-name-nondirectory byte-compile-current-file)
-		     "esh-module.el")
-	      ;; When eshell file names are expanded from a wildcard
-	      ;; or by reading the Eshell directory, e.g. when they
-	      ;; say "make recompile" in the lisp directory, Emacs on
-	      ;; MS-DOS sees a truncated name "esh-modu.el" instead of
-	      ;; "esh-module.el".
-	      (and (fboundp 'msdos-long-file-names)
-		   (null (msdos-long-file-names))
-		   (equal (file-name-nondirectory byte-compile-current-file)
-			  "esh-modu.el"))))
-    (let* ((directory (file-name-directory byte-compile-current-file))
-	   (elc-file (expand-file-name "esh-groups.elc" directory)))
-      (eshell-load-defgroups directory)
-      (if (file-exists-p elc-file) (delete-file elc-file)))))
-
-(load "esh-groups" t t)
+(require 'esh-groups)
 
 ;;; User Variables: