Makefile.am: Make HTML doc building depend on stamp file

This patch also adds an explicit list of all files written by
sphinx (“docoutput”).

By using an explicit list the build process is more predictable
and will allow us to include the NEWS file again.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

Makefile.am

@@ -48,7 +48,7 @@ MAINTAINERCLEANFILES = \
 	$(maninput)
 
 maintainer-clean-local:
-	-rm -rf doc/api doc/build doc/html
+	rm -rf doc/api doc/html
 
 CLEANFILES = \
 	autotools/replace_vars.sed \
@@ -150,16 +150,18 @@ docrst = \
 	doc/rapi.rst \
 	doc/security.rst
 
-doc/html: $(docrst) $(docpng) doc/conf.py configure.ac
+doc/html/.stamp: $(docrst) $(docpng) doc/conf.py configure.ac
 	@test -n "$(SPHINX)" || \
 	    { echo 'sphinx-build' not found during configure; exit 1; }
-	mkdir -p doc/build/doctrees
-	PYTHONPATH=.:$(top_builddir) $(SPHINX) -q -b html \
-	    -d doc/build/doctrees \
+	PYTHONPATH=. $(RUN_IN_TEMPDIR) $(SPHINX) -q -b html \
+	    -d . \
 	    -D version="$(VERSION_MAJOR).$(VERSION_MINOR)" \
 	    -D release="$(PACKAGE_VERSION)" \
-	    $(top_srcdir)/doc doc/html
-	touch "$@"
+	    $(abs_top_srcdir)/doc $(CURDIR)/doc/html
+	rm -f doc/html/.buildinfo doc/html/objects.inv
+	touch $@
+
+doc/html: doc/html/.stamp
 
 docdot = \
 	doc/arch-2.0.dot \