Fixed cursor resource leak in Windows (thanks Huib-Jan Imbens!)

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40507

src/video/wincommon/SDL_sysmouse.c

@@ -95,6 +95,8 @@ static void memxor(Uint8 *dst, Uint8 *src1, Uint8 *src2, int len)
 void WIN_FreeWMCursor(_THIS, WMcursor *cursor)
 {
 #ifndef USE_STATIC_CURSOR
+	if ( cursor->curs == GetCursor() )
+		SetCursor(NULL);
 	if ( cursor->curs != NULL )
 		DestroyCursor(cursor->curs);
 	if ( cursor->ands != NULL )