clapper-app: Retain compatibility with older graphviz

src/bin/clapper-app/clapper-app-utils.c

@@ -610,7 +610,16 @@ _create_pipeline_svg_file_in_thread (GTask *task, GObject *source G_GNUC_UNUSED,
 
   gvc = gvContext ();
   gvLayout (gvc, graph, "dot");
+
+#ifdef HAVE_GVC_13
   gvRenderData (gvc, graph, "svg", &img_data, &size);
+#else
+  {
+    guint tmp_size = 0; // Temporary uint to satisfy older API
+    gvRenderData (gvc, graph, "svg", &img_data, &tmp_size);
+    size = tmp_size;
+  }
+#endif
 
   agclose (graph);
   gvFreeContext (gvc);

src/bin/clapper-app/meson.build

@@ -105,6 +105,9 @@ if not pp_option.disabled()
   if cgraph_dep.found() and gvc_dep.found()
     clapperapp_c_args += ['-DHAVE_GRAPHVIZ']
     clapperapp_deps += [cgraph_dep, gvc_dep]
+    if gvc_dep.version().version_compare('>= 13.0.0')
+      clapperapp_c_args += ['-DHAVE_GVC_13']
+    endif
     clapperapp_available_functionalities += 'pipeline-preview'
   elif pp_option.enabled()
     error('pipeline-preview option was enabled, but required dependencies were not found')