diff --git a/Makefile.am b/Makefile.am
index ff5f61b58..3686103b5 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1543,6 +1543,7 @@ test_util_SOURCES = \
 	src/test/test-util.c
 
 test_util_LDADD = \
+	-lm \
 	libsystemd-core.la
 
 test_uid_range_SOURCES = \