From f6cbbb63654d3c0d778b634eb25802f6654ab777 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 22 Jun 2016 11:12:36 +0530
Subject: [PATCH] Old Ubuntu has libsystemd without sd_listen_fds()

---
 src/calibre/srv/pre_activated.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/calibre/srv/pre_activated.py b/src/calibre/srv/pre_activated.py
index cd71376b53..ec0274885c 100644
--- a/src/calibre/srv/pre_activated.py
+++ b/src/calibre/srv/pre_activated.py
@@ -33,6 +33,7 @@ if islinux:
 
     try:
         systemd = ctypes.CDLL(ctypes.util.find_library('systemd'))
+        systemd.sd_listen_fds
     except Exception:
         pass
     else: