Index: src/Makefile.in
--- src/Makefile.in.orig
+++ src/Makefile.in
@@ -597,7 +597,7 @@ include_HEADERS = rrd.h rrd_format.h rrd_client.h
 rrdcgi_SOURCES = rrd_cgi.c
 rrdcgi_LDADD = librrd.la librrdupd.la
 rrdupdate_SOURCES = rrdupdate.c
-rrdupdate_LDADD = librrdupd.la
+rrdupdate_LDADD = librrdupd.la -lpthread
 rrdtool_SOURCES = rrd_tool.c
 rrdtool_DEPENDENCIES = librrd.la
 rrdtool_LDADD = librrd.la