Generate the manual html documentation in the proper build directory

* doc/manuals/Makefile.am: Renamed doc/manuals/Makefile into this.
	(BUILDDIR): Make this variable point to $(builddir)/_build as
	opposed to just _build previously.
	(SOURCEDIR): New variable that points to the source dir as known
	by the autotools magic.
	(ALLSPHINXOPTS): Make the source dir refer to the new
	$(SOURCEDIR), rather than just '.' as previously.
	* configure.ac (doc/manuals/Makefile): Generate this now.
	* doc/Makefile.am: Link the sub-directory doc/manuals.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>

configure.ac

@@ -144,12 +144,13 @@ fi
 
 AC_CONFIG_FILES([Makefile
 libabigail.pc
-include/Makefile
-include/abg-version.h
-doc/Makefile
-src/Makefile
-tools/Makefile
-tests/Makefile])
+  include/Makefile
+  include/abg-version.h
+  doc/Makefile
+    doc/manuals/Makefile
+  src/Makefile
+  tools/Makefile
+  tests/Makefile])
 
 AC_OUTPUT
 

doc/Makefile.am

@@ -1,3 +1,4 @@
+SUBDIRS = manuals
 
 html: $(DO_HTML)
 install-html: $(DO_INSTALL_HTML)

doc/manuals/Makefile.am

@@ -1,16 +1,16 @@
 # Makefile for Sphinx documentation
-#
 
 # You can set these variables from the command line.
 SPHINXOPTS    =
 SPHINXBUILD   = sphinx-build
 PAPER         =
-BUILDDIR      = _build
+BUILDDIR      = $(builddir)/_build
+SOURCEDIR     = $(srcdir)
 
 # Internal variables.
 PAPEROPT_a4     = -D latex_paper_size=a4
 PAPEROPT_letter = -D latex_paper_size=letter
-ALLSPHINXOPTS   = -d $(BUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
+ALLSPHINXOPTS   = -d $(BUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) $(SOURCEDIR)
 # the i18n builder cannot share the environment and doctrees with the others
 I18NSPHINXOPTS  = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .