Include a reference to crashinfo(8).
Add a second argument to proc:::exec-success which consists of the full
argv of the new process. This isn't easily obtainable otherwise (AFAIK).
- Invert the meaning of the -S option.
- Document the -S option.
- Don't explicitly carp to stderr unless !do_syslog is true (syslog(3)
  will do this).
- Fix some style bugs.
- Take into account the amount time spent in syslog(3) (if any) when
  calculating the sleep interval.