```
fails:Process.spawn sets the umask if given the :umask option
fails:Process.spawn raises an Errno::EACCES or Errno::EISDIR when passed a directory
fails:Process.spawn defaults :close_others to true
hangs:Process.spawn when passed close_others: true closes file descriptors >= 3 in the child process even if fds are set close_on_exec=false
linux:Process.spawn inside Dir.chdir kills extra chdir processes
```