pythonPackages.weboob: fix build

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

@@ -40,6 +40,13 @@ in buildPythonPackage rec {
     }; p' weboob/browser/browsers.py weboob/browser/pages.py
   '';
 
+  # Would fail with `Could not find executable: pyuic5`.
+  # That executable will be looked up from an environment variable
+  # in this format when available
+  #
+  # See: https://git.weboob.org/weboob/weboob/blob/1.3/setup.py#L32
+  PYUIC5_EXECUTABLE = "${pyqt5}/bin/pyuic5";
+
   setupPyBuildFlags = ["--qt" "--xdg"];
 
   checkInputs = [ nose ];