[VOL-5051] - Triage bbsim build

[VOL-5092] - verify_bbsim_unit-test repository failures in jenkins job history.

makefiles/*
-----------
  o Merge in latest library makefiles.
  o Some legacy retained:
      tools.mk => makefiles/docker/include.mk
      makefiles/lint/docker/*.mk (replace with docker/include.mk.new)

Makefile
--------
  o Remove bogus foobar target.
  o Target docs-lint now maps to library target lint-doc8.

docs/Makefile
-------------
  o venv install now handled by makefiles/virtualenv.mk
  o Replaced inlined doc8 lint target with makefiles/lint/doc8 (lint-doc8)
  o Use std defines for SHELL= and other constants.
  o Replace separator ';' with '&&' in commands using venv (detect errors).

config.mk
---------
  o Enable lint targets for doc8, docker & json.
  o More lint checks can be enabled but cleanup is needed first.

docs/Makefile
requirements.txt
----------------
  o Identified a few python module problems documented in VOL-5092.
  o Makefile wild target(%) matching stray dependencies so hardcode sphinx targets to act on.
  o Added hyphen/success to "make docs" until VOL-5092 can be straightened out.

Change-Id: Ibe4006747ee610bfe8ac0fdbb339e5e18e6e9176
diff --git a/makefiles/lint/yaml.mk b/makefiles/lint/yaml.mk
index c9cb392..8672daa 100644
--- a/makefiles/lint/yaml.mk
+++ b/makefiles/lint/yaml.mk
@@ -1,8 +1,8 @@
 # -*- makefile -*-
 # -----------------------------------------------------------------------
-# Copyright 2017-2022 Open Networking Foundation
+# Copyright 2017-2023 Open Networking Foundation (ONF) and the ONF Contributors
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
+# 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
 #
@@ -15,18 +15,71 @@
 # limitations under the License.
 # -----------------------------------------------------------------------
 
-YAML_FILES ?= $(error YAML_FILES= is required)
+$(if $(DEBUG),$(warning ENTER))
 
-.PHONY: lint-yaml
+##-------------------##
+##---]  GLOBALS  [---##
+##-------------------##
+.PHONY: lint-yaml lint-yaml-all lint-yaml-modified
 
-lint : lint-yaml
+## -----------------------------------------------------------------------
+## Intent: Use the yaml command to perform syntax checking.
+##   o If UNSTABLE=1 syntax check all sources
+##   o else only check sources modified by the developer.
+## Usage:
+##   % make lint UNSTABLE=1
+##   % make lint-yaml-all
+## -----------------------------------------------------------------------
 
-lint-yaml: vst_venv
-	source ./$</bin/activate \
-	    ; set -u \
-	    ; yamllint -s $(YAML_FILES)
+ifndef NO-LINT-YAML
+  have-yaml-files := $(if $(strip $(YAML_FILES)),true)
+  YAML_FILES      ?= $(error YAML_FILES= is required)
 
+  lint-yaml-mode := $(if $(have-yaml-files),modified,all)
+  lint-yaml : lint-yaml-$(lint-yaml-mode)
+
+  lint : lint-yaml#     # Enable as a default lint target
+endif# NO-LINT-YAML
+
+## -----------------------------------------------------------------------
+## Intent: exhaustive yaml syntax checking
+## -----------------------------------------------------------------------
+lint-yaml-all:
+	$(HIDE)$(MAKE) --no-print-directory lint-yaml-install
+
+	find . \( -iname '*.yaml' -o -iname '*.yml' \) -print0 \
+	    | $(xargs-n1-clean) yamllint --strict
+
+## -----------------------------------------------------------------------
+## Intent: check deps for format and python3 cleanliness
+## Note:
+##   yaml --py3k option no longer supported
+## -----------------------------------------------------------------------
+lint-yaml-modified:
+	$(HIDE)$(MAKE) --no-print-directory lint-yaml-install
+	yamllint -s $(YAML_FILES)
+
+## -----------------------------------------------------------------------
+## Intent:
+## -----------------------------------------------------------------------
+lint-yaml-install:
+	@echo
+	@echo "** -----------------------------------------------------------------------"
+	@echo "** yaml syntax checking"
+	@echo "** -----------------------------------------------------------------------"
+	yamllint --version
+	@echo
+
+## -----------------------------------------------------------------------
+## Intent: Display command usage
+## -----------------------------------------------------------------------
 help::
-	@echo "  lint-yaml            Syntax check yaml source using yamllint"
+	@echo '  lint-yaml          Syntax check python using the yaml command'
+  ifdef VERBOSE
+	@echo '  lint-yaml-all       yaml checking: exhaustive'
+	@echo '  lint-yaml-modified  yaml checking: only locally modified'
+  endif
+
+$(if $(DEBUG),$(warning LEAVE))
 
 # [EOF]