network-graphs: use graphviz without X

nix/pkgs/network-graphs.nix

@@ -1,7 +1,5 @@
-{ config, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 let
-  inherit (pkgs) lib runCommand graphviz;
-
   netColor = net:
     if net == "core"
     then "grey"
@@ -82,13 +80,13 @@ let
     }
   '';
   renderGraph = args@{ name, engine, ... }:
-    runCommand "${name}.png" {
+    pkgs.runCommand "${name}.png" {
       src = builtins.toFile "${name}.dot" (
         toDot args
       );
     } ''
       echo $src
-      ${graphviz}/bin/${engine} -Tpng $src > $out
+      ${pkgs.graphviz-nox}/bin/${engine} -Tpng $src > $out
     '';
 
 in rec {
@@ -162,7 +160,7 @@ in rec {
           ) (builtins.attrNames containers);
       };
 
-  network-graphs = runCommand "network-graphs" {} ''
+  network-graphs = pkgs.runCommand "network-graphs" {} ''
     DIR=$out/share/doc/zentralwerk
     mkdir -p $DIR
     ln -s ${physical-graph} $DIR/physical.png