Add to the ss (subsystem) library the ability to dynamically link
to the readline library if it is present in the system. 

diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
index a9a6c63..e6bcdba 100644
--- a/debugfs/debugfs.c
+++ b/debugfs/debugfs.c
@@ -1576,6 +1576,7 @@
 		ss_perror(sci_idx, retval, "creating invocation");
 		exit(1);
 	}
+	ss_get_readline(sci_idx);
 
 	(void) ss_add_request_table (sci_idx, &ss_std_requests, 1, &retval);
 	if (retval) {