Solaris implementation of the Puppet::Util::AtFork handler. The callbacks defined in this implementation ensure the forked process runs in a different contract than the parent process. This is necessary in order for the child process to be able to survive termination of the contract its parent process runs in. This is needed notably for an agent run executed by a puppet agent service to be able to restart that service without being killed in the process as a consequence of running in the same contract as the service, as all processes in the contract are killed when the contract is terminated during the service restart.