[m-rev.] for review: replace direct error printouts with error_specs

[Julien Fischer]

Hi Zoltan,

On Tue, 11 Jan 2022, Zoltan Somogyi wrote:

>

The beginning of this log message is missing.

> compiler/check_libgrades.m:
>     Replace some direct printouts of error messages with the error_specs.
> 
> compiler/make.program_target.m:
> compiler/make.top_level.m:
>     Transmit these error specs to the level level, then print them out,
>     together with any other error specs, some of which have not been
>     converted from direct printouts to error specs yet.
>
>     In make.top_level.m, break up a too-large predicate.
> 
> compiler/error_util.m:
>     Add a form of simplest_spec that does not have an associated context,
>     for situations such as the above.
> 
> compiler/options_file.m:
>     Make the interface of a predicate less error prone.
> 
> compiler/mercury_compile_main.m:
> compiler/mode_errors.m:
>     Conform to the changes above.

The rest looks fine.

Julien.