Link against event_extra and event_core not event.

--- libevent.pc.in.orig	Mon Sep 19 01:02:59 2011
+++ libevent.pc.in	Mon Sep 19 01:03:15 2011
@@ -10,7 +10,7 @@ Description: libevent is an asynchronous notification 
 Version: @VERSION@
 Requires:
 Conflicts:
-Libs: -L${libdir} -levent
+Libs: -L${libdir} -levent_extra -levent_core
 Libs.private: @LIBS@
 Cflags: -I${includedir}
 
