Index: configure.ac
--- configure.ac.orig
+++ configure.ac
@@ -32,6 +32,10 @@ AC_CHECK_LIB([event],
 	[event_init],
 	,
 	[AC_MSG_ERROR([libevent is required to build idleconn])])
+AC_CHECK_LIB([eventextra],
+	[evdns_init],
+	,
+	[AC_MSG_ERROR([libeventextra is required to build idleconn])])
 fi