make: Check for Sphinx before checking docs

Signed-off-by: Stephen Finucane <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>

Documentation/automake.mk

@@ -101,18 +101,21 @@ ALLSPHINXOPTS = -W -n -d $(SPHINXBUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHIN
 sphinx_verbose = $(sphinx_verbose_@AM_V@)
 sphinx_verbose_ = $(sphinx_verbose_@AM_DEFAULT_V@)
 sphinx_verbose_0 = -q
+
+if HAVE_SPHINX
 htmldocs:
 	$(AM_V_GEN)$(SPHINXBUILD) $(sphinx_verbose) -b html $(ALLSPHINXOPTS) $(SPHINXBUILDDIR)/html
 ALL_LOCAL += htmldocs
-.PHONY: htmldocs
 
 check-docs:
 	$(SPHINXBUILD) -b linkcheck $(ALLSPHINXOPTS) $(SPHINXBUILDDIR)/linkcheck
-.PHONY: check-docs
 
 clean-docs:
 	rm -rf $(SPHINXBUILDDIR)/doctrees
 	rm -rf $(SPHINXBUILDDIR)/html
 	rm -rf $(SPHINXBUILDDIR)/linkcheck
 CLEAN_LOCAL += clean-docs
+endif
+.PHONY: htmldocs
+.PHONY: check-docs
 .PHONY: clean-docs

configure.ac

@@ -97,6 +97,7 @@ OVS_CHECK_LOGDIR
 OVS_CHECK_PYTHON
 OVS_CHECK_PYTHON3
 OVS_CHECK_FLAKE8
+OVS_CHECK_SPHINX
 OVS_CHECK_DOT
 OVS_CHECK_IF_PACKET
 OVS_CHECK_IF_DL

m4/openvswitch.m4

@@ -400,7 +400,7 @@ else:
    AM_CONDITIONAL([HAVE_PYTHON3], [test "$HAVE_PYTHON3" = yes])])
 
 
-dnl Checks for dot.
+dnl Checks for flake8.
 AC_DEFUN([OVS_CHECK_FLAKE8],
   [AC_CACHE_CHECK(
     [for flake8],
@@ -412,6 +412,18 @@ AC_DEFUN([OVS_CHECK_FLAKE8],
      fi])
    AM_CONDITIONAL([HAVE_FLAKE8], [test "$ovs_cv_flake8" = yes])])
 
+dnl Checks for sphinx.
+AC_DEFUN([OVS_CHECK_SPHINX],
+  [AC_CACHE_CHECK(
+    [for sphinx],
+    [ovs_cv_sphinx],
+    [if sphinx-build --version >/dev/null 2>&1; then
+       ovs_cv_sphinx=yes
+     else
+       ovs_cv_sphinx=no
+     fi])
+   AM_CONDITIONAL([HAVE_SPHINX], [test "$ovs_cv_sphinx" = yes])])
+
 dnl Checks for dot.
 AC_DEFUN([OVS_CHECK_DOT],
   [AC_CACHE_CHECK(