bug#19547: Patch for this bug

[Eli Zaretskii <eliz@gnu.org>]

> From: Thierry Volpiatto <thierry.volpiatto@gmail.com>
> Cc: Reuben Thomas <rrt@sc3d.org>,  19547@debbugs.gnu.org
> Date: Fri, 25 Nov 2016 18:10:15 +0100
> 
> 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 ?

Sure, and thanks for working on this.

> > 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 ?

You can do that with a 'switch' in C, or, better, with a C array that
holds the symbols and their corresponding C event_kind values, like
this:

 struct event_value {
   Lisp_Object event_symbol;
   enum event_kind event_kind;
 };
 static struct event_value symbol_to_kind[] = {
   { Qfocus_in, FOCUS_IN_EVENT },
   { Qhelp, HELP_EVENT },
   { Qiconify, ICONIFY_EVENT },
   ...
 };

Then, for each symbol, you can find the corresponding event value by
walking the array until you find a match.