osmo-stat-dummy: add rate counters and statsd tester

It's handy for testing rate counters as well as statsd metrics.

Related: OS#5671
Change-Id: Ibd8b17aa3ba9ceb527c6231310f01d736fb542a7
diff --git a/utils/Makefile.am b/utils/Makefile.am
index 712f01a..80d1566 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -29,6 +29,10 @@
 endif
 
 if ENABLE_EXT_TESTS
+SUBDIRS = \
+	osmo-stat-dummy \
+	$(NULL)
+
 if ENABLE_GB
 noinst_PROGRAMS += osmo-ns-dummy
 osmo_ns_dummy_SOURCES = osmo-ns-dummy.c osmo-ns-dummy-vty.c