Utilities/Sphinx: Add OpenSearch link to html page headers on cmake.org

Reference an OpenSearch description file that sits outside the content
of any specific version so we only need to maintain one and so that
it can reference the latest version.

This was previously added in a custom branch for building the
cmake.org reference documentation.

2 files changed, 6 insertions, 0 deletions

diff --git a/Utilities/Sphinx/CMakeLists.txt b/Utilities/Sphinx/CMakeLists.txt
index dd70ce6852..14d0e14f56 100644
--- a/Utilities/Sphinx/CMakeLists.txt
+++ b/Utilities/Sphinx/CMakeLists.txt
@@ -139,6 +139,7 @@ set(doc_html_opts "")
 if(CMake_SPHINX_CMAKE_ORG)
   list(APPEND doc_html_opts
     -A googleanalytics=1
+    -A opensearch=1
     -A versionswitch=1
     )
 
diff --git a/Utilities/Sphinx/templates/layout.html b/Utilities/Sphinx/templates/layout.html
index d02b44d9e3..8fb7c42732 100644
--- a/Utilities/Sphinx/templates/layout.html
+++ b/Utilities/Sphinx/templates/layout.html
@@ -31,6 +31,11 @@
 {%- endblock %}
 
 {% block extrahead %}
+  {%- if opensearch is defined %}
+    <link rel="search" type="application/opensearchdescription+xml"
+          title="Search within CMake Documentation of Latest Version"
+          href="{{ pathto('../latest-opensearch.xml', 1) }}"/>
+  {%- endif %}
   {%- if versionswitch is defined %}
     <script type="text/javascript" src="{{ pathto('../version_switch.js', 1) }}"></script>
   {%- endif %}