github release (golang mia) debugging.

jjb/shell/github-release.sh
---------------------------
  o Temporarily disable exit-on-failure within displayCommand().
  o Allow progression toward manifestation of the original failure.
  o Shellcheck cleanups.

jjb/verify/bbsim.yaml
---------------------
  o Remove v2.9 & v2.10 job placeholders, must have misheard the request
    earlier because the need now is only for v2.11 views.

packer/provision/basebuild.sh
-----------------------------
  o shellcheck: quote $(go env GOPATH) to prevent word/path splitting.

makefiles/
----------
  o Added library makefiles/ subdirectory to support more lint targets.
  o Makefile proper will need to be updated.

Change-Id: Icc766b90ffe798fe12c0376787f2298a68babbd4
diff --git a/makefiles/virtualenv.mk b/makefiles/virtualenv.mk
new file mode 100644
index 0000000..008a372
--- /dev/null
+++ b/makefiles/virtualenv.mk
@@ -0,0 +1,33 @@
+# -*- makefile -*-
+## -----------------------------------------------------------------------
+# Copyright 2017-2022 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.
+## -----------------------------------------------------------------------
+
+## usage:   {target} : venv-req
+# venv : .venv/bin/activate requirements.txt
+venv-dep : .venv/bin/activate
+venv-req : .venv/bin/activate requirements.txt
+
+.venv/bin/activate:
+	virtualenv -p python3 $@
+	source ./$@/bin/activate \
+	   pip install --upgrade pip \
+	source ./$@/bin/activate \
+	   pip install --upgrade setuptools \
+	[[ -r requirements.txt ]]       \
+	    && source ./$@/bin/activate \
+	    && python -m pip install -r requirements.txt
+
+# [EOF]