[syslinux] Label scope

[Collins, Jeremy]

I currently have a menu system with multiple submenus. I switch menus
reloading vesamenu.c32 and the submenu's config file for each submenu. I
want convert my existing menu system into one config file with multiple
layers of menus using ' MENU BEGIN' and 'MENU END'. I have the
impression that the conversion can be done:

-- old --
LABEL menuA
  MENU LABEL Menu A
  KERNEL vesamenu.c32
  APPEND subA.cfg

-- new --
MENU BEGIN Menu A
  INCLUDE subA.cfg
MENU END

However if / when I do this I'm unclear if a label name for an
particular item is in scope only for that MENU section it is declared
inside or if it needs to be globally unique. For example if the
resulting menu (after includes) was something like the one below, would
it be valid and would LOCALBOOT get executed on timeout?

ONTIMEOUT default

MENU BEGIN Menu A
  LABEL default 
    KERNEL hdt.c32

  MENU BEGIN Menu A1
    LABEL default 
      KERNEL vmlinuz1
  MENU END

  MENU BEGIN Menu A2
    LABEL default 
      KERNEL vmlinuz2
  MENU END

MENU END

LABEL default
  LOCALBOOT 0