Build guide/next/ for next MacPorts release

This makes use of DocBook profiling using the audience="" attribute.

Example:
<para audience="2.4">This is for users of MacPorts 2.4.x</para>
<para audience="2.5">This is for users of MacPorts 2.5.0 or later</para>

See the DocBook XSL guide for all details:
http://www.sagehill.net/docbookxsl/Profiling.html

Makefile

@@ -51,14 +51,24 @@ GUIDE_XSL_CHUNK = $(GUIDE)/resources/chunk.xsl
 # DocBook HTML stylesheet for the guide.
 STYLESHEET = docbook.css
 
-.PHONY: all guide guide-chunked guide-dblatex clean validate
+# MacPorts versions
+MACPORTS_RELEASED = 2.4 2.4.0 2.4.1 2.4.2
+MACPORTS_NEXT     = 2.5 2.5.0 2.4.3
 
-all: guide guide-chunked
+gen_audience = $(subst $(eval) ,;,$1)
+MACPORTS_RELEASED_AUDIENCE = $(call gen_audience,$(MACPORTS_RELEASED))
+MACPORTS_NEXT_AUDIENCE = $(call gen_audience,$(MACPORTS_NEXT))
+
+.PHONY: all guide guide-next guide-chunked guide-chunked-next guide-dblatex clean validate
+
+all: guide guide-next guide-chunked guide-chunked-next
 
 # Generate the HTML guide using DocBook from the XML sources
 guide: GUIDE_OUTDIR= $(GUIDE_RESULT)
+guide-next: GUIDE_OUTDIR = $(GUIDE_RESULT)/next
 guide-chunked: GUIDE_OUTDIR = $(GUIDE_RESULT)/chunked
-guide-chunked: GUIDE_XSL = $(GUIDE_XSL_CHUNK)
+guide-chunked-next: GUIDE_OUTDIR = $(GUIDE_RESULT)/next/chunked
+guide-chunked guide-chunked-next: GUIDE_XSL = $(GUIDE_XSL_CHUNK)
 
 $(GUIDE)/resources/xsl:
 ifeq ($(UNAME), Linux)
@@ -67,12 +77,14 @@ else
 	$(LN) -sfh $(DOCBOOK) $(GUIDE)/resources/xsl
 endif
 
-guide guide-chunked:: $(GUIDE)/resources/xsl
+guide guide-next guide-chunked guide-chunked-next:: $(GUIDE)/resources/xsl
 	$(MKDIR) -p $(GUIDE_OUTDIR)
 	$(CP) $(GUIDE)/resources/$(STYLESHEET) $(GUIDE_OUTDIR)/$(STYLESHEET)
 	$(CP) $(GUIDE)/resources/images/* $(GUIDE_OUTDIR)/
 	$(CP) $(GUIDE)/resources/*.js $(GUIDE_OUTDIR)/
 	$(XSLTPROC) --xinclude \
+	    --stringparam profile.audience \
+	        "$(if $(filter %-next,$@),$(MACPORTS_NEXT_AUDIENCE),$(MACPORTS_RELEASED_AUDIENCE))" \
 	    --output $(GUIDE_OUTDIR)/index.html \
 	    $(GUIDE_XSL) $(GUIDE_SRC)/guide.xml
 	# Convert all sections (h1-h9) to a link so it's easy to link to them.
@@ -81,22 +93,28 @@ guide guide-chunked:: $(GUIDE)/resources/xsl
 	    's|(<h[0-9] [^>]*><a id="([^"]*)"></a>)([^<]*)(</h[0-9]>)|\1<a href="#\2">\3</a>\4|g' \
 	    $(GUIDE_OUTDIR)/index.html
 
-guide-chunked::
+guide-chunked guide-chunked-next::
 	# Add the table of contents to every chunked HTML file.
 	# If someone knows a better way to do this please change it.
 	$(TCLSH) toc-for-chunked.tcl $(GUIDE_OUTDIR)
 
 # Generate the guide as a PDF.
 guide-dblatex: SUFFIX = pdf
-guide-dblatex:
+guide-dblatex: $(GUIDE)/resources/xsl
 	$(MKDIR) -p $(GUIDE_RESULT_DBLATEX)
+	$(XSLTPROC) --xinclude \
+	    --stringparam profile.audience \
+		"$(if $(filter %-next,$@),$(MACPORTS_NEXT_AUDIENCE),$(MACPORTS_RELEASED_AUDIENCE))" \
+	    --output $(GUIDE_RESULT_DBLATEX)/guide.xml \
+	     $(GUIDE)/resources/xsl/profiling/profile.xsl \
+	     $(GUIDE_SRC)/guide.xml
 	$(DBLATEX) \
 		--fig-path="$(GUIDE)/resources/images" \
 		--type="$(SUFFIX)" \
 		--param='toc.section.depth=2' \
 		--param='doc.section.depth=3' \
 		--output="$(GUIDE_RESULT_DBLATEX)/macports-guide.$(SUFFIX)" \
-	$(GUIDE_SRC)/guide.xml
+		$(GUIDE_RESULT_DBLATEX)/guide.xml
 
 # Remove all temporary files generated by guide:.
 clean: