VOL-4977 Failure in voltha-protos verification job.

Makefile
makefiles/consts.mk
makefiles/virtualenv.mk
-----------------------
  o Update to use library makefile virtualenv.mk to create .venv
    and remove by clean/sterile target.
  o Construct commands using '&&' -vs- ';' to better detect errors.
  o pip install packages relocated into the requirements.txt file.
  o Separate extra deps from target rule since they are never
    processed by the target rule.
  o Added banners for readabilty.

makefiles/lint/golang/sca.mk
makefiles/lint/golang/include.mk
--------------------------------
  o lint target for golang sources.

Tested with python v3.10 (localhost) and v2.7 (docker container).
Debug to see if hangs are dependent on the patch reported in vol-4977.

Change-Id: I0783f6fb347bf2cd15350f9e17fc19695343b7ac
diff --git a/makefiles/lint/golang/sca.mk b/makefiles/lint/golang/sca.mk
index eeecc42..20af593 100644
--- a/makefiles/lint/golang/sca.mk
+++ b/makefiles/lint/golang/sca.mk
@@ -17,12 +17,32 @@
 
 $(if $(DEBUG),$(warning ENTER))
 
-GOLANG_FILES ?= $(error PYTHON_FILES= is required)
+##-------------------##
+##---]  GLOBALS  [---##
+##-------------------##
+.PHONY: lint-golang lint-golang-sca-all lint-golang-sca-modified
 
-.PHONY: lint-golang-sca
+GOLANG_FILES ?= $(error GOLANG_FILES= is required)
 
-lint : lint-golang-sca
+$(info loading)
+## -----------------------------------------------------------------------
+## Intent: Use the golang 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-golang-all
+## -----------------------------------------------------------------------
+ifndef NO-LINT-GOLANG
+  lint-golang-mode := $(if $(have-golang-files),modified,all)
+  lint : lint-golang-sca-$(lint-golang-mode)
 
+  lint-golang-all      : lint-golang-sca-all
+  lint-golang-modified : lint-golang-sca-modified
+endif# NO-LINT-GOLANG
+
+## -----------------------------------------------------------------------
+## Intent: exhaustive golint syntax checking
 ## -----------------------------------------------------------------------
 ## Intent: Run goformat on files on sandbox files.
 ##   1) find . -name '*.go' -print0
@@ -47,13 +67,47 @@
   lint-golang-sca-args += -w
 endif
 
-lint-golang-sca:
-	find . -name '*.go' -print0 \
-	    | xargs $(lint-golang-sca-xargs) gofmt -d -s
+gofmt-args += -d# Do not output reformatted lines
+# gofmt-args += -e# Display all errors (including spurious)
+gofmt-args += -s# Try to simplify code
 
-help::
-	@echo "  lint-golang-sca            Syntax check golang sources"
-	@echo "    MODIFIER: FIX=1          Correct problems (gofmt -d -s -w)"
+## -----------------------------------------------------------------------
+## Intent: exhaustive golang syntax checking
+## -----------------------------------------------------------------------
+lint-golang-sca-all: $(venv-activate-script)
+#       $(MAKE) --no-print-directory lint-sca-install
+
+	find . -name '*.go' -print0 \
+	    | xargs $(lint-golang-sca-xargs) gofmt $(gofmt-args)
+
+## -----------------------------------------------------------------------
+## Intent: check deps for format and cleanliness
+## -----------------------------------------------------------------------
+lint-golang-sca-modified: lint-golang-all
+#	$(MAKE) --no-print-directory lint-golang-sca-install
+
+	gofmt $(gofmt-args) $(GOLANG_FILES)
+
+## -----------------------------------------------------------------------
+## Intent: Tool installation as needed
+## -----------------------------------------------------------------------
+.PHONY: lint-golang-sca-install
+lint-golang-sca-install:
+	@echo
+	@echo "** -----------------------------------------------------------------------"
+	@echo "** golang syntax checking"
+	@echo "** -----------------------------------------------------------------------"
+	@echo
+
+## -----------------------------------------------------------------------
+## Intent: Display target help
+## -----------------------------------------------------------------------
+.PHONY: help-golang-sca
+help-verbose += help-golang-sca
+help-golang-sca :
+	@echo "  % $(MAKE) lint-golang GOLANG_FILES=..."
+	@echo '  lint-golang-sca-modified  golang checking: only modified'
+	@echo '  lint-golang-sca-all       golang checking: exhaustive'
 
 $(if $(DEBUG),$(warning LEAVE))