gnome.nautilus-python: fix loading gi

pkgs/desktops/gnome/misc/nautilus-python/default.nix

···
-{ lib, stdenv
+{ stdenv
+, lib
+, substituteAll
 , fetchurl
 , pkg-config
 , which
···
     url = "mirror://gnome/sources/${pname}/${lib.versions.majorMinor version}/${pname}-${version}.tar.xz";
     sha256 = "161050sx3sdxqcpjkjcpf6wl4kx0jydihga7mcvrj9c2f8ly0g07";
   };
+
+  patches = [
+    # Make PyGObject’s gi library available.
+    (substituteAll {
+      src = ./fix-paths.patch;
+      pythonPaths = lib.concatMapStringsSep ", " (pkg: "'${pkg}/${python3.sitePackages}'") [
+        python3.pkgs.pygobject3
+      ];
+    })
+  ];
 
   nativeBuildInputs = [
     pkg-config

pkgs/desktops/gnome/misc/nautilus-python/fix-paths.patch

···
+diff --git a/src/nautilus-python.c b/src/nautilus-python.c
+index 843e3c6..466a513 100644
+--- a/src/nautilus-python.c
++++ b/src/nautilus-python.c
+@@ -184,6 +184,9 @@ nautilus_python_init_python (void) {
+         return FALSE;
+     }
+ 
++    debug("Add PyGObject to path");
++    PyRun_SimpleString("import site;import functools; functools.reduce(lambda k, p: site.addsitedir(p, k), [@pythonPaths@], site._init_pathinfo())");
++
+     /* import gobject */
+     debug("init_pygobject");
+     if (!np_init_pygobject()) {