BUILD: promex: service-prometheus.c needs tools.h
It calls url_decode() and memprintf() but used to inherit them through
others.
diff --git a/addons/promex/service-prometheus.c b/addons/promex/service-prometheus.c
index ee7c38f..6a42a47 100644
--- a/addons/promex/service-prometheus.c
+++ b/addons/promex/service-prometheus.c
@@ -34,6 +34,7 @@
#include <haproxy/stream.h>
#include <haproxy/stream_interface.h>
#include <haproxy/task.h>
+#include <haproxy/tools.h>
#include <haproxy/version.h>
/* Prometheus exporter applet states (appctx->st0) */