KWSys Process: Workaround child kill trouble on Cygwin
When we kill a child we send SIGSTOP first so that we can traverse its child processes recursively. On unwinding the recursion we then send SIGKILL. Current Cygwin has trouble when both signals are sent in quick succession by the parent process. Add a usleep(1) after sending the first signal to give up our time slice and give Cygwin a chance to process the first signal before sending the second.