chg: forward SIGINT, SIGHUP to process group These signals are meant to send to a process group, instead of a single process: SIGINT is usually emitted by the terminal and sent to the process group. SIGHUP usually happens to a process group if termination of a process causes that process group to become orphaned. Before this patch, chg will only forward these signals to the single server process. This patch changes it to the server process group. This will allow us to properly kill processes started by the forked server process, like a ssh process. The behavior difference can be observed by setting SSH_ASKPASS to a dummy script doing "sleep 100" and then run "chg push ssh://dest-need-password-auth". Before this patch, the first Ctrl+C will kill the hg process while ssh-askpass and ssh will remain alive. This patch will make sure they are killed properly.