Move control panel applet enumeration to cpanelfolder.c.

diff --git a/dlls/shell32/cpanel.h b/dlls/shell32/cpanel.h
index 1d37d98..aa6b499 100644
--- a/dlls/shell32/cpanel.h
+++ b/dlls/shell32/cpanel.h
@@ -20,6 +20,8 @@
 #ifndef __WINE_SHELL_CPANEL_H
 #define __WINE_SHELL_CPANEL_H
 
+#include "cpl.h"
+
 typedef struct CPlApplet {
     struct CPlApplet*   next;		/* linked list */
     HWND		hWnd;