--- a/src/makefile.unix
+++ b/src/makefile.unix
@@ -30,6 +30,7 @@
    -l boost_filesystem$(BOOST_LIB_SUFFIX) \
    -l boost_program_options$(BOOST_LIB_SUFFIX) \
    -l boost_thread$(BOOST_LIB_SUFFIX) \
+   -l boost_chrono$(BOOST_LIB_SUFFIX) \
    -l db_cxx$(BDB_LIB_SUFFIX) \
    -l ssl \
    -l crypto