bug#51449: 28.0.50; iso-transl overwrites alt key bindings

[Gregory Heytings]

Your bug report is difficult to understand.

> In emacs -Q just need something to get the Alt key bound
> e.g.
> (setq  mac-command-modifier 'alt)
>
> The when you Type A-c you get ¢ and you cannot bind it yourself.

If you do this, A-c should display "A-c is undefined", which is indeed the 
case, it's not bound to any command (in emacs -Q).

> On a mac I want the key by space to be Alt as that is what is printed on 
> my PC keyboard. I suspect this is true with PCs

If you want the key on the left of the space bar to be the Meta key in 
Emacs (which is what the Alt key usually does), you should do: (setq 
mac-command-modifier 'meta).

> The issue is that (require 'iso-transl) is called before the user can 
> alter its behaviour and that iso-transl.el then binds to various A-c and 
> other keys.

The use of the Alt modifier is indeed hardcoded in iso-transl.  If you 
want to use it, you can chose another modifier key on your keyboard, for 
example: (setq mac-right-command-modifier 'alt).  In that case the key on 
the left of your space bar will be Meta, and the key on the right of your 
space bar will be Alt.