PR 13722 candidate fix

[Arnaud Charlet]

> IMO, Ada is broken until "make bootstrap -jN && make install" does
> everything that is needed to produce a functioning compiler.

Given the numerous bugs opened or discussed regularly about various
problems with parallel bootstrap for various reasons, I don't see that
Ada is much different here.

> I've been bitten by this more times than I care to count, and I
> personally refuse to deal with Ada until it's corrected.

I personally don't care until there's a properly filed PR in bugzilla :-)
I just did two different queries and did not find any trace of the isue
you mention (that's actually the first time I hear about it. The only
other parallel issues reported with Ada have been fixed some time ago
already). So you know what you should do...

You might even find out that what you are complaining about no longer is
an issue (that's the advantage of having a PR in bugzilla, you can watch
progress on thee issues).

And in any case, I'm glad to see that more and more people are actually
enabling Ada, and detecting regressions earlier and earlier, so that these
can be investigated and/or reverted when needed.

Arno