[m-rev.] for review: bugfix for io.set_environment_var/4

[Mark Brown]

Hi,

On Mon, Apr 18, 2016 at 9:49 AM, Julien Fischer <jfischer at opturion.com> wrote:
> I know that the most recent version of Mark's diff removed the mutable,
> but I think it's worth mentioning: please try to avoid using mutables in
> the standard library.  If something that depends on them ends up being
> called by the library intialisation code all sorts of hard-to-debug
> stuff can occur.

Yes, you're right. Also, there was a race condition in updating the
mutable, so that change didn't completely fix the bug anyway.

Cheers,
Mark