open_pipes() bugfix

+ write "exit" to STDERR (like bash)
+ set_last_exit_status() on CTRL-C

srcs/signals.c

@@ -14,11 +14,11 @@
 
 void	sigint_handler_interactive(int signum)
 {
-	(void)signum;
 	write(1, "\n", 1);
 	rl_on_new_line();
 	rl_replace_line("", 1);
 	rl_redisplay();
+	set_last_exit_status(EXIT_SIGNAL + signum);
 }
 
 void	sigint_handler_heredoc(int signum)