bug#46990: 28.0.50; popup menu not navigable via arrow keys on lucid build

[Visuwesh]

[திங்கள் ஜூன் 20, 2022] Po Lu via "Bug reports for GNU Emacs, the Swiss army 
knife of text editors" wrote:

> Colin Baxter <m43cap@yandex.com> writes:
>
>> I suppose the Lucid issue with no key-navigation of a popup menu is not
>> so important since the problem disappears (for me) once the Lucid
>> compiled emacs is installed. Perhaps it might be worth a note to this
>> effect in the INSTALL documentation?
>
> Ah.  Then it's this:
>
> /* For debug, if installation-directory is non-nil this is not an installed
>    Emacs.   In that case we do not grab the keyboard to make it easier to
>    debug. */
> #define GRAB_KEYBOARD  (EQ (Vinstallation_directory, Qnil))
>
> and it's not a bug.

`installation-directory' is non-nil for me yet I can navigate the menus
with the keyboard.

    installation-directory is a variable defined in ‘C source code’.

    Its value is "/home/viz/lib/ports/emacs/"