Improve docs Makefile to do full build

Include the make apidoc and breathe-apidoc steps in the documentation
Makefile for ease of use. In this way, depart from the Makefile
generated automatically by Sphinx.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/docs/Makefile b/docs/Makefile
index d4bb2cb..6a7599e 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -12,9 +12,27 @@
 help:
 	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
 
-.PHONY: help Makefile
+.PHONY: help clean apidoc breathe_apidoc Makefile
+
+# Intercept the 'clean' target so we can do the right thing for apidoc as well
+clean:
+	@# Clean the apidoc
+	$(MAKE) -C .. apidoc_clean
+	@# Clean the sphinx docs
+	@$(SPHINXBUILD) -M clean "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+apidoc:
+	@# Generate doxygen from source using the main Makefile
+	$(MAKE) -C .. apidoc
+
+breathe_apidoc: apidoc
+	@# Remove existing files - breathe-apidoc skips them if they're present
+	rm -rf ./api
+	@# Generate RST file structure with breathe-apidoc
+	breathe-apidoc -o ./api ../apidoc/xml
 
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
-%: Makefile
+%: Makefile breathe_apidoc
+	@# Build the relevant target with sphinx
 	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)