Added xxx_Unregister() functions to all common controls.

diff --git a/include/progress.h b/include/progress.h
index 319367e..b7fe153 100644
--- a/include/progress.h
+++ b/include/progress.h
@@ -20,6 +20,8 @@
   COLORREF    ColorBk;      /* Background color */
 } PROGRESS_INFO;
 
-extern void PROGRESS_Register (void);
+
+extern VOID PROGRESS_Register (VOID);
+extern VOID PROGRESS_Unregister (VOID);
 
 #endif  /* __WINE_PROGRESS_H */