Retire unused sphinx builders

One exception could be the changes builder, but if we ever reach the
point where we can automate the changelog initial creation we can bring
it back.

doc/sphinx/Makefile.am

@@ -4,25 +4,16 @@
 # You can set these variables from the command line.
 SPHINXOPTS    =
 SPHINXBUILD   = $(SPHINX) -W -q -N
-PAPER         = a4
 BUILDDIR      = build
 
-ALLSPHINXOPTS   = -d $(BUILDDIR)/doctrees -D latex_elements.papersize=$(PAPER) $(SPHINXOPTS) $(builddir)
+ALLSPHINXOPTS   = -d $(BUILDDIR)/doctrees $(SPHINXOPTS) $(builddir)
 
-.PHONY: help clean html dirhtml pickle json htmlhelp qthelp latex changes linkcheck doctest
+.PHONY: help clean html linkcheck doctest
 
 help:
 	@echo "Please use \`make <target>' where <target> is one of"
 	@echo "  html      to make standalone HTML files"
-	@echo "  dirhtml   to make HTML files named index.html in directories"
-	@echo "  pickle    to make pickle files"
-	@echo "  json      to make JSON files"
-	@echo "  htmlhelp  to make HTML files and a HTML help project"
-	@echo "  qthelp    to make HTML files and a qthelp project"
-	@echo "  latex     to make LaTeX files, you can set PAPER=a4 or PAPER=letter"
-	@echo "  changes   to make an overview of all changed/added/deprecated items"
 	@echo "  linkcheck to check all external links for integrity"
-	@echo "  doctest   to run all doctests embedded in the documentation (if enabled)"
 
 clean:
 	-rm -rf $(BUILDDIR)/* $(CLEANFILES)
@@ -53,59 +44,12 @@ html: sphinx_prereq
 	@echo
 	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
 
-dirhtml: sphinx_prereq
-	$(SPHINXBUILD) -b dirhtml $(ALLSPHINXOPTS) $(BUILDDIR)/dirhtml
-	@echo
-	@echo "Build finished. The HTML pages are in $(BUILDDIR)/dirhtml."
-
-pickle: sphinx_prereq
-	$(SPHINXBUILD) -b pickle $(ALLSPHINXOPTS) $(BUILDDIR)/pickle
-	@echo
-	@echo "Build finished; now you can process the pickle files."
-
-json: sphinx_prereq
-	$(SPHINXBUILD) -b json $(ALLSPHINXOPTS) $(BUILDDIR)/json
-	@echo
-	@echo "Build finished; now you can process the JSON files."
-
-htmlhelp: sphinx_prereq
-	$(SPHINXBUILD) -b htmlhelp $(ALLSPHINXOPTS) $(BUILDDIR)/htmlhelp
-	@echo
-	@echo "Build finished; now you can run HTML Help Workshop with the" \
-	      ".hhp project file in $(BUILDDIR)/htmlhelp."
-
-qthelp: sphinx_prereq
-	$(SPHINXBUILD) -b qthelp $(ALLSPHINXOPTS) $(BUILDDIR)/qthelp
-	@echo
-	@echo "Build finished; now you can run "qcollectiongenerator" with the" \
-	      ".qhcp project file in $(BUILDDIR)/qthelp, like this:"
-	@echo "# qcollectiongenerator $(BUILDDIR)/qthelp/Varnish.qhcp"
-	@echo "To view the help file:"
-	@echo "# assistant -collectionFile $(BUILDDIR)/qthelp/Varnish.qhc"
-
-latex: sphinx_prereq
-	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
-	@echo
-	@echo "Build finished; the LaTeX files are in $(BUILDDIR)/latex."
-	@echo "Run \`make all-pdf' or \`make all-ps' in that directory to" \
-	      "run these through (pdf)latex."
-
-changes: sphinx_prereq
-	$(SPHINXBUILD) -b changes $(ALLSPHINXOPTS) $(BUILDDIR)/changes
-	@echo
-	@echo "The overview file is in $(BUILDDIR)/changes."
-
 linkcheck: sphinx_prereq
 	$(SPHINXBUILD) -b linkcheck $(ALLSPHINXOPTS) $(BUILDDIR)/linkcheck
 	@echo
 	@echo "Link check complete; look for any errors in the above output " \
 	      "or in $(BUILDDIR)/linkcheck/output.txt."
 
-doctest: sphinx_prereq
-	$(SPHINXBUILD) -b doctest $(ALLSPHINXOPTS) $(BUILDDIR)/doctest
-	@echo "Testing of doctests in the sources finished, look at the " \
-	      "results in $(BUILDDIR)/doctest/output.txt."
-
 EXTRA_DIST = \
 	conf.py \
 	dev-guide \