build-sys: add make rules for documentation

Author: keszybz

Makefile

@@ -1,5 +1,20 @@
+PYTHON = python
 SED = sed
+SPHINX_BUILD = sphinx-build
 INCLUDE_DIR = /usr/include/
+VERSION := $(shell $(PYTHON) setup.py --version)
+
+define buildscript
+import sys,sysconfig
+print("build/lib.{}-{}.{}".format(sysconfig.get_platform(), *sys.version_info[:2]))
+endef
+
+builddir := $(shell $(PYTHON) -c '$(buildscript)')
 
 systemd/id128-constants.h: $(INCLUDE_DIR)/systemd/sd-messages.h
 	$(SED) -n -r 's/,//g; s/#define (SD_MESSAGE_[A-Z0-9_]+)\s.*/add_id(m, "\1", \1) JOINER/p' <$< >$@
+
+SPHINXOPTS = -D version=$(VERSION) -D release=$(VERSION)
+sphinx-%:
+	PYTHONPATH=$(builddir) $(SPHINX_BUILD) -b $* $(SPHINXOPTS) docs build/docs
+	@echo Output has been generated in build/docs