Creating an ActorSystem freezes in Alpine 3.8

[1ma]

Hi, I messaged you a few days ago on Reddit about this bug. I've pinned down the freezing to the moment an ActorSystem is instantiated:

<?php

echo "123\n";
$as = new phactor\ActorSystem();
echo "456\n";

outputs:

123

I've put together a Dockerfile with an environment that reproduces the issue, if that helps (I've also recorded its build log, the logs relevant to phactor start at L903, though I see nothing wrong).