bug#63808: 30.0.50; Infinite loop in info-lookup-guess-gdb-script-symbol

[Eli Zaretskii]

> From: nvp <noah.v.peart@gmail.com>
> Date: Tue, 30 May 2023 14:35:44 -0700
> 
> In a gdb-script-mode buffer, eg. .gdbinit with the cursor (|) in
> the following position:
> 
> de|
> 
> Calling `M-x info-complete-symbol' causes an infinite loop.

Thanks, should be fixed now on the emacs-29 branch.

> In the
> function `info-lookup-guess-gdb-script-symbol' the result
> of `nbutlist' isn't being assigned back to variable.

It doesn't have to, because nbutlast modifies its argument
destructively (except when it doesn't ;-).