libsecret: Use env.prepend() for test environment setup

Starting from GLib / gobject-introspection 2.80, GLib introspection data
is provided by GLib itself instead of gobject-introspection. This causes
tests failures because env.set() resets the environment and GLib is missing
from GI_TYPELIB_PATH:

gi.RepositoryError: Typelib file for namespace 'Gio', version '2.0' not found

pkgs/development/libraries/libsecret/default.nix

@@ -1,6 +1,7 @@
 { stdenv
 , lib
 , fetchurl
+, fetchpatch2
 , glib
 , meson
 , ninja
@@ -33,6 +34,14 @@ stdenv.mkDerivation rec {
     hash = "sha256-Fj0I14O+bUq5qXnOtaT+y8HZZg08NBaMWBMBzVORKyA=";
   };
 
+  patches = [
+    # https://gitlab.gnome.org/GNOME/libsecret/-/merge_requests/141
+    (fetchpatch2 {
+      url = "https://gitlab.gnome.org/GNOME/libsecret/-/commit/208989323211c756dff690115e5cbde5ef7491ce.patch";
+      hash = "sha256-DtRbqyyoMttEYf6B16m9O72Yjurv6rpbnqH7AlrAU4k=";
+    })
+  ];
+
   depsBuildBuild = [
     pkg-config
   ];