Add doc revision to C++ for OpenCL in Makefile (#739)

This commit adds a document revision according to this scheme:

DocRev<YYYY.MM>

- where YYYY is a year of the release
- and MM is a month of the release

This revisioning will divorce the document versioning from the
language versioning, providing an easy way to reference the
document independent from the language versions it describes.

Co-authored-by: Sven van Haastregt <sven.vanhaastregt@arm.com>

Makefile

@@ -68,20 +68,36 @@ SPECREVISION = $(shell echo `git describe --tags --dirty`)
 SPECREMARK = from git branch: $(shell echo `git symbolic-ref --short HEAD`) \
 	     commit: $(shell echo `git log -1 --format="%H"`)
 endif
-
-ATTRIBOPTS_NO_VERSION	= -a revdate="$(SPECDATE)" \
-			  -a revremark="$(SPECREMARK)" \
+# The C++ for OpenCL document revision scheme is aligned with its release date.
+# Revision naming scheme is as follows:
+# DocRevYYYY.MM,
+# where YYYY corresponds to its release year,
+# MM corresponds to its release month.
+# Example for the release in Dec 2021 the revision is DocRev2021.12.
+# Leave as 'DocRevYYYY.MM-Next' if the doc content does not correspond to any official revision.
+# where DocRevYYYY.MM is the last released revision.
+CXX4OPENCL_DOCREVISION = DocRev2021.12
+CXX4OPENCL_DOCREMARK = $(SPECREMARK) \
+			tag: $(SPECREVISION)
+
+COMMONATTRIBOPTS	= -a revdate="$(SPECDATE)" \
 			  -a stem=latexmath \
 			  -a generated=$(GENERATED) \
 			  -a sectnumlevels=5
 
 ATTRIBOPTS   = -a revnumber="$(SPECREVISION)" \
-	       $(ATTRIBOPTS_NO_VERSION)
+	       -a revremark="$(SPECREMARK)" \
+	       $(COMMONATTRIBOPTS)
+
+CXX4OPENCL_ATTRIBOPTS   = -a revnumber="$(CXX4OPENCL_DOCREVISION)" \
+			  -a revremark="$(CXX4OPENCL_DOCREMARK)" \
+			  $(COMMONATTRIBOPTS)
+
 
 ADOCEXTS	      = -r $(CURDIR)/config/sectnumoffset-treeprocessor.rb \
 	-r $(CURDIR)/config/spec-macros.rb \
 	-r $(CURDIR)/config/rouge_opencl.rb
-ADOCOPTS_NO_VERSION   = -d book $(ATTRIBOPTS_NO_VERSION) $(NOTEOPTS) $(VERBOSE) $(ADOCEXTS)
+CXX4OPENCL_ADOCOPTS   = -d book $(CXX4OPENCL_ATTRIBOPTS) $(NOTEOPTS) $(VERBOSE) $(ADOCEXTS)
 ADOCCOMMONOPTS	      = -a apispec="$(CURDIR)/api" \
 			-a config="$(CURDIR)/config" \
 			-a cspec="$(CURDIR)/c" \
@@ -352,14 +368,14 @@ CXX4OPENCLDOCSRC = $(CXX4OPENCLDOC).txt $(GENDEPENDS) \
 cxx4openclhtml: $(HTMLDIR)/$(CXX4OPENCLDOC).html $(CXX4OPENCLDOCSRC)
 
 $(HTMLDIR)/$(CXX4OPENCLDOC).html: $(CXX4OPENCLDOCSRC) $(KATEXINST)
-	$(QUIET)$(ASCIIDOCTOR) -b html5 $(ADOCOPTS_NO_VERSION) $(ADOCHTMLOPTS) -o $@ $(CXX4OPENCLDOC).txt
+	$(QUIET)$(ASCIIDOCTOR) -b html5 $(CXX4OPENCL_ADOCOPTS) $(ADOCHTMLOPTS) -o $@ $(CXX4OPENCLDOC).txt
 
 cxx4openclpdf: $(PDFDIR)/$(CXX4OPENCLDOC).pdf $(CXX4OPENCLDOCSRC)
 
 $(PDFDIR)/$(CXX4OPENCLDOC).pdf: $(CXX4OPENCLDOCSRC)
 	$(QUIET)$(MKDIR) $(PDFDIR)
 	$(QUIET)$(MKDIR) $(PDFMATHDIR)
-	$(QUIET)$(ASCIIDOCTOR) -b pdf $(ADOCOPTS_NO_VERSION) $(ADOCPDFOPTS) -o $@ $(CXX4OPENCLDOC).txt
+	$(QUIET)$(ASCIIDOCTOR) -b pdf $(CXX4OPENCL_ADOCOPTS) $(ADOCPDFOPTS) -o $@ $(CXX4OPENCLDOC).txt
 ifndef GS_EXISTS
 	$(QUIET) echo "Warning: Ghostscript not installed, skipping pdf optimization"
 else