[VOL-5031] Build and deploy voltha-onos for v2.12

makefiles/*
-----------
  o https://github.com/opencord/onf-make
  o Update to the latest library makefiles to support more lint targets.

VERSION
-------
  o Cosmetic dev version bump to triage build state.

Change-Id: Iaddd825c24afdfa13e99cfd46cfe887072016d0f
diff --git a/makefiles/help/variables.mk b/makefiles/help/variables.mk
new file mode 100644
index 0000000..a22b179
--- /dev/null
+++ b/makefiles/help/variables.mk
@@ -0,0 +1,36 @@
+# -*- makefile -*-
+# -----------------------------------------------------------------------
+# Copyright 2017-2023 Open Networking Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# -----------------------------------------------------------------------
+
+# Include variables.mk after library makefiles have been included
+
+ifdef VERBOSE
+  help :: help-variables
+else
+  help ::
+	@echo
+	@echo '[VARIABLES] - Conditional makefile behavior'
+	@echo '  see also: help-variables'
+endif
+
+help-variables:
+	@echo
+	@echo '[VARIABLES] - Conditional makefile behavior'
+	@echo '  NO_PATCHES=           Do not apply patches to the python virtualenv'
+	@echo '  NO_OTHER_REPO_DOCS=   No foreign repos, only apply target to local sources.'
+	@echo '  VERBOSE=              Display extended help topics'
+
+# [EOF]