[RFA] Add constant CMD_LIST_AMBIGUOUS to replace (struct cmd_list_element *) -1

[Michael Snyder]

Tom Tromey wrote:
>>>>>> "Michael" == Michael Snyder <msnyder@vmware.com> writes:
> 
> Michael> OK?
> Michael> 2011-03-11  Michael Snyder  <msnyder@vmware.com>
> Michael> 	* cli/cli-decode.h (CMD_LIST_AMBIGUOUS): Define.
> Michael> 	* cli/cli-decode.c (lookup_cmd_1): Use CMD_LIST_AMBIGUOUS.
> Michael> 	(lookup_cmd): Test for CMD_LIST_AMBIGUOUS.
> Michael> 	* completer.c (complete_line_internal): Use CMD_LIST_AMBIGUOUS.
> Michael> 	* top.c (set_verbose): Use CMD_LIST_AMBIGUOUS.
> 
> Looks good to me.

Thanks, committed.