makefiles/
----------
  o Adding more lint target logic.
  o Copy in virtualenv.mk from voltha-docs to support dependency
    based virtualenv installations.

*/*.yaml
--------
  o Misc yamllint cleanups.

Makefile
--------
  o Prune inlined logic since replaced by library makefile logic.
  o Replaced explicit pyenv installation with dependency driven
    so venv will only require installation once per target run.
  o Library make clean/sterile targets handle cleanup.

Change-Id: Ie2ce0ebc01b07c0004a5904c2641c394e46d5044
diff --git a/makefiles/lint/makefile.mk b/makefiles/lint/makefile.mk
new file mode 100644
index 0000000..8ebe9c3
--- /dev/null
+++ b/makefiles/lint/makefile.mk
@@ -0,0 +1,45 @@
+# -*- makefile -*-
+# -----------------------------------------------------------------------
+# Copyright 2022 Open Networking Foundation (ONF) and the ONF Contributors
+# -----------------------------------------------------------------------
+
+##-------------------##
+##---]  GLOBALS  [---##
+##-------------------##
+xargs-n1-local := $(subst -t,$(null),$(xargs-n1))#   inhibit cmd display
+
+# Gather sources to check
+# TODO: implement deps, only check modified files
+make-check-find := find . -name 'vendor' -prune
+make-check-find += -o \( -iname makefile -o -name '*.mk' \)
+make-check-find += -type f -print0
+
+make-check      := $(MAKE)
+
+make-check-args += --dry-run
+make-check-args += --keep-going
+make-check-args += --warn-undefined-variables
+make-check-args += --no-print-directory
+
+# Quiet internal undef vars
+make-check-args += DEBUG=
+
+##-------------------##
+##---]  TARGETS  [---##
+##-------------------##
+ifndef NO-LINT-MAKEFILE
+  lint : lint-make
+endif
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+lint-make:
+	$(HIDE)$(env-clean) $(make-check-find) \
+	    | $(xargs-n1-local) $(make-check) $(make-check-args)
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+help ::
+	@echo '  lint-make                     Syntax check [Mm]akefile and *.mk'
+
+# [EOF]