>> - I suspect there's some good reason I'm not aware of why we don't
>>   eb539e92e9 at all (this is not necessary to fix the reported issue
>>   tho).
>
> Like I said earlier, I always thought that this problem doesn't affect
> the pdumper builds.  Perhaps that's not true with native-compilation?

I can't see any good reason not to warn about purespace overflow,
regardless if it leads to misbehavior or not: we clearly do want to size
the purespace to avoid overflow.