chg: forward job control signals to worker process (issue5051) This is necessary to suspend/resume long pulls, interactive curses session, etc. The implementation is based on emacsclient, but our version doesn't test if chg process is foreground or not before propagating SIGCONT. This is because chg isn't always an interactive session. If we copy the SIGTTIN/SIGTTOU emulation from emacsclient, non-interactive session can't be moved to a background job. $ chg pull ^Z suspended $ bg %1 [1] continued [1] suspended (tty input) # wrong https://github.com/emacs-mirror/emacs/blob/0e96320/lib-src/emacsclient.c#L1094