Comment 12 for bug 1851263

I've verified that at least my issue is resolved by this:

```
docker run -it --rm ubuntu:18.04
apt update
apt install g++ wget
wget https://sourceware.org/bugzilla/attachment.cgi?id=11382 -O bug23861.c
sed -i 's/do_exit = 0/do_exit(0)/' bug23861.c
g++ bug23861.c -lpthread -o bug23861
for ((x=1;x<100;x++)) ; do echo $x;date;./bug23861 --prefer-writer-nonrecursive;done
```

The above hands, now if we try to update to the newer proposed version.

```
apt install lsb-release
cat <<EOF >/etc/apt/sources.list.d/ubuntu-$(lsb_release -cs)-proposed.list
# Enable Ubuntu proposed archive
deb http://archive.ubuntu.com/ubuntu/ $(lsb_release -cs)-proposed restricted main multiverse universe
EOF
apt update
apt install libc6
for ((x=1;x<100;x++)) ; do echo $x;date;./bug23861 --prefer-writer-nonrecursive;done
```

Now it keeps going without crashing.