Bug#841935: pbuilder: incorrect permissions on /dev/ptmx breaks openpty()

[Ansgar Burchardt]

Thorsten Glaser writes:
> … whereas all “new” chroots look like…
>
> ls: cannot access 'base.cow-xenial-amd64/dev/pts/ptmx': No such file or directory
> lrwxrwxrwx 1 root root 8 Mai 10 14:10 base.cow-xenial-amd64/dev/ptmx -> pts/ptmx
>
> … so I assume that something in debootstrap changed so that
> there is now a symlink created instead of a proper device node.
>
> Maybe the debootstrap maintainers can comment on this?

That looks like the same issue as I reported in sbuild in #817236 (which
severity maybe should be raised if this is an issue for more packages):
there needs to be a mount for /dev/pts to accommodate for the changes in
debootstrap (and optionally a bind mount for /dev/ptmx if there are
still old chroots around).

Ansgar