[Backport release-25.11] unison: 2.53.7 -> 2.53.8 (#464960)

diff --git a/src/make_tools.ml b/src/make_tools.ml

index a5792b6..4f4d037 100644

--- a/src/make_tools.ml

+++ b/src/make_tools.ml

@@ -475,7 +475,7 @@ let shell_internal ?(err_null = false) ?exit_status ?(input_str = "") cmd =

     Unix.handle_unix_error (fun () ->

       if err_null || input_str <> "" then

         let (sh_out, sh_in, _) as sh_full =

-          Unix.open_process_full cmd [|"PATH=" ^ env.$("PATH")|] in

+          Unix.open_process_full cmd (Array.append (Unix.environment ()) [|"PATH=" ^ env.$("PATH")|]) in

         if input_str <> "" then begin

           output_string sh_in input_str;

           flush sh_in

stdenv.mkDerivation (finalAttrs: {

  pname = "unison";

  version = "2.53.7";

  version = "2.53.8";

  src = fetchFromGitHub {

    owner = "bcpierce00";

    repo = "unison";

    rev = "v${finalAttrs.version}";

    hash = "sha256-QmYcxzsnbRDQdqkLh82OLWrLF6v3qzf1aOIcnz0kwEk=";

    hash = "sha256-ynsu9jLGFtjlzmHZtOdLEH5G6eXFAhZs9UayYrmKqp0=";

  };

  # Allow the build scripts to correctly call ocamlfind & detect dependencies

  patches = [ ./fix-ocamlfind-env.patch ];

  strictDeps = true;

  nativeBuildInputs = [