docs: Generate gst-plugins-rs documentation

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2954>

.gitlab-ci.yml

@@ -663,7 +663,7 @@ valgrind ges:
     - '.build_ccache_vars'
   variables:
     MESON_ARGS: *simple_build
-    MESON_BUILDTYPE_ARGS: "-Ddoc=enabled"
+    MESON_BUILDTYPE_ARGS: "-Ddoc=enabled -Drs=enabled"
     # Disable werror for the docs build, we don't need it
     MESON_GST_WERROR: ''
     CI_ARTIFACTS_URL: "${CI_PROJECT_URL}/-/jobs/${CI_JOB_ID}/artifacts/raw/"

meson.build

@@ -117,7 +117,7 @@ subprojects = [
   ['pygobject', { 'option': get_option('python'), 'match_gst_version': false, 'sysdep': 'pygobject-3.0', 'sysdep_version': '>= 3.8' }],
   ['gst-python', { 'option': get_option('python')}],
   ['gst-examples', { 'option': get_option('gst-examples'), 'match_gst_versions': false}],
-  ['gst-plugins-rs', { 'option': get_option('rs'), 'match_gst_version': false}],
+  ['gst-plugins-rs', { 'option': get_option('rs'), 'build-hotdoc': true, 'match_gst_version': false}],
 ]
 
 symlink = '''

subprojects/gst-docs/meson.build

@@ -67,13 +67,13 @@ if built_subprojects != ''
         if sub.get_variable('build_hotdoc')
             message('Building @0@ documentation'.format(project_name))
 
-            foreach lib: sub.get_variable('libs_doc')
+            foreach lib: sub.get_variable('libs_doc', [])
               hotdoc_subprojects += [lib]
               libs += lib.full_path() + pathsep
               deps += [lib]
             endforeach
 
-            foreach plugin_doc: sub.get_variable('plugins_doc')
+            foreach plugin_doc: sub.get_variable('plugins_doc', [])
               plugins_doc += plugin_doc.full_path() + pathsep
               hotdoc_subprojects += [plugin_doc]
               deps += [plugin_doc]