See which files in the Linux userland are actually used

I would like to see which files in the Linux userland are actually used so that I can slim down the set of shipped files accordingly.

According to https://forums.FreeBSD.org/threads/linux-compatability-monitor-files-accessed-by-linux-app.62029/post-358476 this should work but it doesn't:

```
FreeBSD% sudo kldload dtrace
FreeBSD% sudo dtrace -n ':linux64:linux_open:entry { printf("%s", copyinstr((uintptr_t)args[1]->path)); }'
dtrace: invalid probe specifier :linux64:linux_open:entry { printf("%s", copyinstr((uintptr_t)args[1]->path)); }: probe description :linux64:linux_open:entry does not match any probes
```

According to https://wiki.freebsd.org/DTrace/One-Liners this should

> Trace file opens with process and filename:

```
FreeBSD% sudo dtrace -n 'syscall::open*:entry { printf("%s %s", execname, copyinstr(arg0)); }'
dtrace: invalid probe specifier syscall::open*:entry { printf("%s %s", execname, copyinstr(arg0)); }: probe description syscall::open*:entry does not match any probes
```

What am I missing?