Add code to kill stopped (or partially stopped) jobs with SIGHUP on exit.

POSIX says that _exit() should do this, but on GNO it doesn't. This implementation should match the POSIX behavior in most cases, although it's not exactly the same.

Gsh also kills jobs on exit, but does so whether they're stopped or not and uses SIGKILL.

shell/hush.c

@@ -1428,6 +1428,27 @@ void _exit_wrapper(int status) {
 
 	if (getpid() == G.last_execed_pid) {
 		// We're the root shell or one that's been exec'd...
+# if ENABLE_HUSH_JOB
+		struct pipe *job;
+		/* Send SIGHUP followed by SIGCONT to kill pgrps of jobs with 
+		 * stopped commands (unless they intentionally ignore SIGHUP).
+		 * 
+		 * This behavior roughly approximates the POSIX spec for sending
+		 * signals when a process exits, although it doesn't match it
+		 * exactly (it may miss stopped descendants that aren't direct
+		 * children).  It's different from gsh, which sends SIGKILL to 
+		 * all jobs, whether running or stopped (but not whole pgrps).
+		 */
+		for (job = G.job_list; job; job = job->next) {
+			if (job->pgrp <= 0 || job->alive_cmds == 0)
+				continue;
+			if (job->stopped_cmds == 0)
+				continue;
+			debug_printf_exec(("HUPing pgrp %d\n", job->pgrp));
+			if (kill(- job->pgrp, SIGHUP) == 0)
+				kill(- job->pgrp, SIGCONT);
+		}
+# endif	
 		// Call regular _exit()
 		if (stackcheck)
 			fprintf(stderr, "hush stack usage (pid %i): %i bytes\n", getpid(), _endStackCheck());