Of note is that `unlockpt` is required, both by the standard, and our
implementation. This has been taken care of inside of `openpty`, which
is the only non-libc way we are acquiring ptys. Additionally, it has
been modified such that it is POSIX compliant, so any outside future
changes to ptyd will not affect it.
This is part of my ptyd changes (#100). This can be safely merged once
the changes from base/ and userutils/ are merged alongside it.
auronandace