--- ./src/Makefile.am.orig	2013-07-24 09:38:33.088184877 +0000
+++ ./src/Makefile.am	2013-07-24 09:38:48.788333567 +0000
@@ -111,7 +111,7 @@
 
 rrdtool_SOURCES = rrd_tool.c
 rrdtool_DEPENDENCIES = librrd.la
-rrdtool_LDADD	= librrd.la
+rrdtool_LDADD	= librrd.la -lm
 
 rrdcached_SOURCES = rrd_daemon.c
 rrdcached_DEPENDENCIES = librrd_th.la