[m-rev.] for review: fix mantis bug 514

[Zoltan Somogyi]

2020-07-24 15:52 GMT+10:00 "Julien Fischer" <jfischer at opturion.com>:
> I will try it out with GCC 10 over the weekend.  (I don't recall if I
> have a VM lying about that has GCC 10; if not I will create one.)

Thanks.

> We should probably look at defaulting to -fno-common for GCC < 10 (and
> clang too if required).  The GCC manual says there may be a performance
> impact with -fcommon.

Yes, we should, but we need the Microsoft C compiler to have something
equivalent as well.
 
> Add a comment at the head of runtime/mercury_builtin_types.h pointing out that
> all these places need to be updated if the arity of a builtin type changes.

There is already a very similar comment just above the block of definitions :-(

Thanks for the review.

Zoltan.