util: enable unit-tests

Start write tests and fix a missing header inclusion.

Change-Id: I4e56323f972b1358dc83a4cb61c25f98cda2a479
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/test/Makefile.am b/test/Makefile.am
index 4d5ca63..2a51c00 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -13,7 +13,7 @@
 
 # Run all 'check' test programs
 check_PROGRAMS = sensor_manager_unittest sensor_pluggable_unittest \
- sensor_host_unittest
+ sensor_host_unittest util_unittest
 TESTS = $(check_PROGRAMS)
 
 # Until libconfig is mocked out or replaced, include it.
@@ -25,3 +25,6 @@
 
 sensor_host_unittest_SOURCES = sensor_host_unittest.cpp
 sensor_host_unittest_LDADD = $(top_builddir)/sensors/host.o
+
+util_unittest_SOURCES = util_unittest.cpp
+util_unittest_LDADD = $(top_builddir)/util.o