* dcrt0.cc (do_exit): Don't bother looking for pgrp children to send SIGHUP if

process has never created any children.
* fork.cc (fork): Set flag indicating that there is another process with our
process group.
* spawn.cc (spawn_guts): Ditto.
* pinfo.h (set_has_pgid_children): New methods for setting when process has
children in its process group.
* syscalls.cc (setpgid): Clear has_gid_children if pgid changes.

winsup/cygwin/syscalls.cc

@@ -1711,6 +1711,8 @@ setpgid (pid_t pid, pid_t pgid)
       if (p == myself || p->ppid == myself->pid)
 	{
 	  p->pgid = pgid;
+	  if (p->pid != p->pgid)
+	    p->set_has_pgid_children (0);
 	  res = 0;
 	}
       else