port: allow pressing DEL to delete the binding

port/include/input.h

@@ -20,6 +20,7 @@ enum virtkey {
   VK_KEYBOARD_BEGIN = 0,
   VK_RETURN = 40,
   VK_ESCAPE = 41,
+  VK_DELETE = 76,
 
   /* same order as SDL mouse buttons */
   VK_MOUSE_BEGIN = 512,

port/src/optionsmenu.c

@@ -773,11 +773,19 @@ struct menuitem g_ExtendedBindKeyMenuItems[] = {
 		0,
 		menuhandlerDoBind,
 	},
+	{
+		MENUITEMTYPE_SELECTABLE,
+		0,
+		MENUITEMFLAG_SELECTABLE_CENTRE | MENUITEMFLAG_LITERAL_TEXT,
+		(uintptr_t)"ESC to cancel, DEL to remove binding\n",
+		0,
+		menuhandlerDoBind,
+	},
 	{ MENUITEMTYPE_END },
 };
 
 struct menudialogdef g_ExtendedBindKeyMenuDialog = {
-	MENUDIALOGTYPE_WHITE,
+	MENUDIALOGTYPE_SUCCESS,
 	(uintptr_t)"Bind",
 	g_ExtendedBindKeyMenuItems,
 	NULL,
@@ -882,7 +890,7 @@ static MenuItemHandlerResult menuhandlerDoBind(s32 operation, struct menuitem *i
 
 	const s32 key = inputGetLastKey();
 	if (key && key != VK_ESCAPE) {
-		inputKeyBind(g_BindsPlayer, g_BindContKey, g_BindIndex, key);
+		inputKeyBind(g_BindsPlayer, g_BindContKey, g_BindIndex, (key == VK_DELETE ? 0 : key));
 		menuPopDialog();
 	}