undefined symbol: FAMNoExists

lighttpd won't start.

Steps to reproduce:
$ sudo /usr/sbin/lighttpd
or
$ sudo systemctl start lighttpd

Expected outcome:
daemon starts.

Seen instead:
/usr/sbin/lighttpd: symbol lookup error: /usr/sbin/lighttpd: undefined symbol: FAMNoExists
or
Job for lighttpd.service failed. See "systemctl status lighttpd.service" and "journalctl -xe" for details.
$ systemctl status lighttpd.service -l
May 09 17:53:32 deunan systemd[1]: Starting Lighttpd Daemon...
May 09 17:53:32 deunan lighttpd[8229]: /usr/sbin/lighttpd: symbol lookup error: /usr/sbin/lighttpd: undefined symbol: FAMNoExists

Other info:
`ldd /usr/sbin/lighttpd` does not report any missing shared libraries.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: lighttpd 1.4.35-4ubuntu1
ProcVersionSignature: Ubuntu 3.19.0-16.16-generic 3.19.3
Uname: Linux 3.19.0-16-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.17.2-0ubuntu1
Architecture: i386
Date: Sat May 9 17:51:52 2015
InstallationDate: Installed on 2013-06-08 (700 days ago)
InstallationMedia: Xubuntu 13.04 "Raring Ringtail" - Release i386 (20130423.1)
ProcEnviron:
 LANGUAGE=en_CA:en
 TERM=screen
 PATH=(custom, no user)
 LANG=en_CA.UTF-8
 SHELL=/bin/bash
SourcePackage: lighttpd
UpgradeStatus: Upgraded to vivid on 2015-04-25 (14 days ago)
mtime.conffile..etc.lighttpd.conf.available.10.cgi.conf: 2013-08-02T23:17:55
mtime.conffile..etc.lighttpd.conf.available.10.fastcgi.conf: 2013-09-11T11:19:16