App::CamelPKI::Sys - Operating System-oriented bag of tricks.
All functions are exportable, but none are by default.
Runs $sub in a forked process, and returns the PID it runs under. The child process calls $sub in void context, and terminates when $sub does so; if $sub terminates normally, the exit code of the child process will be 0, otherwise it will be 1. The child process will not perform global destruction, even if $sub contains an explicit call to "exit" in perlfunc.