'cargo build' gets stuck in real_poll_wait()

How to reproduce

apk add rust cargo
cargo init
cargo build

I think the issue is related to file descriptors being corrupted/removed...

```
/proc/15/fd
total 0
lrwxrwxrwx 0 root root 0 Jan 1 1970 0 -> /dev/pts/0
lrwxrwxrwx 0 root root 0 Jan 1 1970 1 -> /dev/pts/0
lrwxrwxrwx 0 root root 0 Jan 1 1970 2 -> /dev/pts/0
lrwxrwxrwx 0 root root 0 Jan 1 1970 3 -> anon_inode:[unknown]
lrwxrwxrwx 0 root root 0 Jan 1 1970 4 -> anon_inode:[unknown]
lrwxrwxrwx 0 root root 0 Jan 1 1970 5 -> anon_inode:[unknown]
lrwxrwxrwx 0 root root 0 Jan 1 1970 6 -> anon_inode:[unknown]
```

The cargo process was/is 15 in this case. Furthermore, it appears the fd 5 is associated with the wedged poll attempt...

**Note that polls->0->fd = 5**

Reproduce the hang with apk add rust cargo, cargo init, and cargo build, then inspect real_poll_wait() and the poll entry whose fd is 5. Use the reported /proc/15/fd state to trace the corrupted or removed descriptors; done means cargo build no longer remains stuck in real_poll_wait().

Written by the indexing model from the issue text.