bug#19547: Patch for this bug

[Thierry Volpiatto <thierry.volpiatto@gmail.com>]

As no body is working on this, I started looking at this as I would like
to have a fix for this for helm, however I have difficulties as my C
level is 0.
Could you please bear with me on some points ?

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Reuben Thomas <rrt@sc3d.org>
>> Date: Wed, 9 Nov 2016 22:03:34 +0000
>> Cc: 19547@debbugs.gnu.org
>> 
>> So, if you could indicate a precise design that would be acceptable, I will implement it. That seems to me a
>> good medium between extending a hard fix that I agree is inelegant, and my spending lots of time trying to
>> understand yet another area of Emacs.
>
> How about the following:
>
> Use DEFVAR_LISP to define a Lisp variable with initial value of Qnil.

Ok for this one (I think).

> In some preloaded Lisp file, say subr.el, give that variable a value,
> a list of symbols that name the events we currently don't consider
> relevant for throw-on-input.

Ok.

> (Those symbols will have to be invented, e.g. 'focus-in' for
> FOCUS_IN_EVENT, etc.)

It is here I don't understand, how do I make the correspondance with e.g
focus-in (the lisp symbol) and FOCUS_IN_EVENT ?

> In kbd_buffer_store_buffered_event, where we set Vquit_flag depending
> on Vthrow_on_input, examine the value of that list variable, and
> ignore any events that have their symbols in the list.

Ok, well you will tell me when I send patch...