[m-dev.] for review: prevent compiler aborts for uu types

[Simon Taylor]

> diff -u -u -r1.271 make_hlds.m
> --- make_hlds.m	1998/08/07 00:49:03	1.271
> +++ make_hlds.m	1998/08/19 05:22:35
> @@ -1006,8 +1006,9 @@
>  			io__stderr_stream(StdErr),
>  			io__set_output_stream(StdErr, OldStream),
>  			prog_out__write_context(Context),
> -			report_warning(StdErr, 
> -	"Warning: undiscriminated union types (`+') not implemented.\n"),
> +			io__write_string(
> +	"Sorry, not implemented: undiscriminated union type.\n"),
> +			io__set_exit_status(1),
>  			io__set_output_stream(OldStream, _)

The error message should point out that the user probably meant `==', not `='.
Otherwise that looks fine.

Simon.