Furthur notes : 1- The signal pipe needs to be rebuilt when you fork off a new process that uses the same kernel. Example would be a pre-forking server. To do this, you need to call $poe_kernel->has_forked.
2- Signals need to be masked while the signal pipe is being rebuilt. We use sigprocmask() for this. This has been tested on cygwin, Mac OS X, Linux and FreeBSD. We don't now how compatible sigprocmask() is with more obscure platforms. -Philip
