Fix build of manifest_tool

Makefile

@@ -100,7 +100,7 @@ MANIFEST_TOOL_EXE=$(MANIFEST_TOOL_DIR)/manifest-tool
 TEST_TLS_EXE=test/tls/tls
 
 # All binaries together in a list
-EXES=$(WEAVER_EXE) $(SIGPROXY_EXE) $(KUBEPEERS_EXE) $(WEAVENPC_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE) $(PLUGIN_EXE) $(RUNNER_EXE) $(TEST_TLS_EXE)
+EXES=$(WEAVER_EXE) $(SIGPROXY_EXE) $(KUBEPEERS_EXE) $(WEAVENPC_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE) $(PLUGIN_EXE) $(RUNNER_EXE) $(TEST_TLS_EXE) $(MANIFEST_TOOL_EXE)
 
 # These stamp files are used to mark the current state of the build; whether an image has been built or not
 BUILD_UPTODATE=.build.uptodate
@@ -160,6 +160,7 @@ $(WEAVENPC_EXE): prog/weave-npc/*.go npc/*.go npc/*/*.go
 $(PLUGIN_EXE): prog/plugin/*.go plugin/*/*.go api/*.go common/*.go common/docker/*.go net/*.go
 $(TEST_TLS_EXE): test/tls/*.go
 $(RUNNER_EXE): tools/runner/*.go
+$(MANIFEST_TOOL_EXE): $(MANIFEST_TOOL_DIR)/*.go
 $(WEAVEWAIT_NOOP_EXE): prog/weavewait/*.go
 $(WEAVEWAIT_EXE): prog/weavewait/*.go net/*.go
 $(WEAVEWAIT_NOMCAST_EXE): prog/weavewait/*.go net/*.go