Re: master d067ac5: Remove more compat code from prolog.el

[Stefan Monnier <monnier@iro.umontreal.ca>]

> @@ -1999,7 +1997,7 @@ Argument BOUND is a buffer position limiting searching."
>           (if (eq prolog-system 'mercury)
>               (list
>                (regexp-opt prolog-directives-i 'words)
> -              0 'prolog-warning-face)))
> +              0 prolog-warning-face)))
>          ;; Inferior mode specific patterns
>          (prompt
>           ;; FIXME: Should be handled by comint already.

I think this one is wrong: the font-lock data-structure built here
should contain at this position an *expression* that returns a face when
passed to `eval`.

IOW with the above change the value held by `prolog-warning-face` needs
to be "an expression that evaluates to a face" rather than "a face name".

This will still work as long as `prolog-warning-face` has value
`font-lock-warning-face` since it's both the name of a face and the name
of an expression whose value is that same face (because it's also the
name of a variable whose value is, by default, itself).


        Stefan