diff -ru a/ceph-0.51/src/Makefile.am b/ceph-0.51/src/Makefile.am
--- a/ceph-0.51/src/Makefile.am	2012-08-26 10:58:03.000000000 +1200
+++ b/ceph-0.51/src/Makefile.am	2012-11-03 02:08:28.286488442 +1300
@@ -1006,7 +1006,7 @@
 libcommon_la_SOURCES = $(libcommon_files)
 libcommon_la_CFLAGS= ${CRYPTO_CFLAGS} ${AM_CFLAGS}
 libcommon_la_CXXFLAGS= ${CRYPTO_CXXFLAGS} ${AM_CXXFLAGS}
-libcommon_la_LDFLAGS = -lrt
+libcommon_la_LDFLAGS = -lrt -lboost_system
 noinst_LTLIBRARIES += libcommon.la
 
 libglobal_la_SOURCES = \