adding Doxygen doc generation to the Sphinx Makefile

doc/Makefile

@@ -6,6 +6,7 @@ SPHINXOPTS    =
 SPHINXBUILD   = sphinx-build
 PAPER         =
 BUILDDIR      = build
+DOXYGENDIR    = doxygen
 
 # User-friendly check for sphinx-build
 ifeq ($(shell which $(SPHINXBUILD) >/dev/null 2>&1; echo $$?), 1)
@@ -50,8 +51,12 @@ help:
 
 clean:
 	rm -rf $(BUILDDIR)/*
+	rm -rf $(DOXYGENDIR)/*
 
 html:
+	@echo "Generating Doxygen documentation..."
+	doxygen Doxyfile
+	@echo "Doxygen documentation generated. \n"
 	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
 	@echo
 	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
@@ -114,6 +119,9 @@ epub:
 	@echo "Build finished. The epub file is in $(BUILDDIR)/epub."
 
 latex:
+	@echo "Generating Doxygen documentation..."
+	doxygen Doxyfile
+	@echo "Doxygen documentation generated. \n"
 	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
 	@echo
 	@echo "Build finished; the LaTeX files are in $(BUILDDIR)/latex."
@@ -121,6 +129,9 @@ latex:
 	      "(use \`make latexpdf' here to do that automatically)."
 
 latexpdf:
+	@echo "Generating Doxygen documentation..."
+	doxygen Doxyfile
+	@echo "Doxygen documentation generated. \n"
 	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
 	@echo "Running LaTeX files through pdflatex..."
 	$(MAKE) -C $(BUILDDIR)/latex all-pdf