xdot: needs graphviz in PATH

pkgs/development/python-modules/xdot/default.nix

@@ -15,6 +15,10 @@ buildPythonPackage rec {
   propagatedBuildInputs = [ gobject-introspection pygobject3 graphviz gtk3 numpy ];
   checkInputs = [ xvfb-run ];
 
+  postInstall = ''
+    wrapProgram "$out/bin/xdot" --prefix PATH : "${lib.makeBinPath [ graphviz ]}"
+  '';
+
   checkPhase = ''
     xvfb-run -s '-screen 0 800x600x24' ${python3.interpreter} nix_run_setup test
   '';

pkgs/top-level/python-packages.nix

@@ -10141,7 +10141,9 @@ in {
 
   xdis = callPackage ../development/python-modules/xdis { };
 
-  xdot = callPackage ../development/python-modules/xdot { };
+  xdot = callPackage ../development/python-modules/xdot {
+    inherit (pkgs) graphviz;
+  };
 
   xenomapper = callPackage ../applications/science/biology/xenomapper { };