mconf/nconf: mark empty menus/menuconfigs different from non-empty ones

Submenus are sometimes empty and it would be nice if there is
something that notifies us that we should not expect any content
_before_ we enter a submenu.

A new function menu_is_empty() was introduced and empty menus and
menuconfigs are now marked by "----" as opposed to non-empty ones that
are marked by "--->".

This scheme was suggested by "Yann E. MORIN" <yann.morin.1998@free.fr>.

Signed-off-by: Dirk Gouders <dirk@gouders.net>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
diff --git a/scripts/kconfig/mconf.c b/scripts/kconfig/mconf.c
index cb8cf4a..6ee4aae 100644
--- a/scripts/kconfig/mconf.c
+++ b/scripts/kconfig/mconf.c
@@ -48,7 +48,7 @@
 "----------\n"
 "o  Use the Up/Down arrow keys (cursor keys) to highlight the item\n"
 "   you wish to change or submenu wish to select and press <Enter>.\n"
-"   Submenus are designated by \"--->\".\n"
+"   Submenus are designated by \"--->\", empty ones by \"----\".\n"
 "\n"
 "   Shortcut: Press the option's highlighted letter (hotkey).\n"
 "             Pressing a hotkey more than once will sequence\n"
@@ -176,7 +176,7 @@
 "\n"),
 menu_instructions[] = N_(
 	"Arrow keys navigate the menu.  "
-	"<Enter> selects submenus --->.  "
+	"<Enter> selects submenus ---> (or empty submenus ----).  "
 	"Highlighted letters are hotkeys.  "
 	"Pressing <Y> includes, <N> excludes, <M> modularizes features.  "
 	"Press <Esc><Esc> to exit, <?> for Help, </> for Search.  "
@@ -498,8 +498,9 @@
 						  menu->data ? "-->" : "++>",
 						  indent + 1, ' ', prompt);
 				} else
-					item_make("   %*c%s  --->", indent + 1, ' ', prompt);
-
+					item_make("   %*c%s  %s",
+						  indent + 1, ' ', prompt,
+						  menu_is_empty(menu) ? "----" : "--->");
 				item_set_tag('m');
 				item_set_data(menu);
 				if (single_menu_mode && menu->data)
@@ -630,7 +631,7 @@
 			  (sym_has_value(sym) || !sym_is_changable(sym)) ?
 			  "" : _(" (NEW)"));
 		if (menu->prompt->type == P_MENU) {
-			item_add_str("  --->");
+			item_add_str("  %s", menu_is_empty(menu) ? "----" : "--->");
 			return;
 		}
 	}