Makefile, configure: Support building rST documentation

Add support to our configure and makefile machinery for building
our rST docs into HTML files.

Building the documentation now requires that sphinx-build is
available; this seems better than allowing half the docs to
be built if it is not present but having half of them missing.
(In particular it means that assuming that distros configured with
--enable-docs they'll get a helpful error from configure telling
them the new build dependency.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190305172139.32662-10-peter.maydell@linaro.org
Message-id: 20190228145624.24885-10-peter.maydell@linaro.org

1 files changed, 13 insertions, 2 deletions

diff --git a/configure b/configure
index cefeb8fcce..47bf617fcc 100755
--- a/configure
+++ b/configure
@@ -4589,13 +4589,24 @@ if compile_prog "" "" ; then
   syncfs=yes
 fi
 
+# Check we have a new enough version of sphinx-build
+has_sphinx_build() {
+    # This is a bit awkward but works: create a trivial document and
+    # try to run it with our configuration file (which enforces a
+    # version requirement). This will fail if either
+    # sphinx-build doesn't exist at all or if it is too old.
+    mkdir -p "$TMPDIR1/sphinx"
+    touch "$TMPDIR1/sphinx/index.rst"
+    sphinx-build -c "$source_path/docs" -b html "$TMPDIR1/sphinx" "$TMPDIR1/sphinx/out" >/dev/null 2>&1
+}
+
 # Check if tools are available to build documentation.
 if test "$docs" != "no" ; then
-  if has makeinfo && has pod2man; then
+  if has makeinfo && has pod2man && has_sphinx_build; then
     docs=yes
   else
     if test "$docs" = "yes" ; then
-      feature_not_found "docs" "Install texinfo and Perl/perl-podlators"
+      feature_not_found "docs" "Install texinfo, Perl/perl-podlators and python-sphinx"
     fi
     docs=no
   fi