start_stop_daemon: add -N <nice> compat
[re]nice: add support for -nNNN w/o spaces, -NNN (nice only),
          simplified code
diff --git a/include/usage.h b/include/usage.h
index c9e5019..ef348a2 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2691,6 +2691,7 @@
 USE_FEATURE_START_STOP_DAEMON_FANCY( \
 	"\n\t-o|--oknodo\t\t\texit status 0 if nothing done" \
 	"\n\t-v|--verbose\t\t\tbe verbose" \
+	"\n\t-N|--nicelevel <N>\t\tadd N to process's nice level" \
 ) \
 	"\n\t-s|--signal <signal>\t\tsignal to send (default TERM)" \
 	"\n\t-U|--chuid <username>|<uid>\tstart process with this name"