Fixed nix workflow

.github/workflows/nix.yml

@@ -45,4 +45,4 @@ jobs:
       - uses: cachix/install-nix-action@v15
         with:
           nix_path: nixpkgs=channel:nixos-unstable
-      - run: nix build
+      - run: nix build .?submodules=1

default.nix

@@ -1,24 +1,14 @@
 { pkgs ? import <nixpkgs> { }
 , lib ? pkgs.lib
 , stdenv ? pkgs.stdenv
-, fetchgit
 }:
-let
-  sexpSource = fetchgit {
-    name = "sexp";
-    url = "https://github.com/rnpgp/sexp.git";
-    rev = "refs/tags/v0.7.0";
-    sha256 = "MA54sKyHBFB6ZAGQCHFswIeiVn/TgTjGhP1dE+fS+sU=";
-  };
-in
+
 stdenv.mkDerivation rec {
   pname = "rnp";
   version = "unstable";
 
   src = ./.;
 
-  sexp = import sexpSource { inherit pkgs; };
-
   buildInputs = with pkgs; [ zlib bzip2 json_c botan2 ];
 
   cmakeFlags = [
@@ -41,7 +31,6 @@ stdenv.mkDerivation rec {
     commitEpoch=$(date +%s)
     baseVersion=$(cat version.txt)
     echo "v$baseVersion-0-g0-dirty+$commitEpoch" > version.txt
-
     # For generating the correct timestamp in cmake
     export SOURCE_DATE_EPOCH=$commitEpoch
   '';
@@ -53,4 +42,4 @@ stdenv.mkDerivation rec {
     platforms = platforms.all;
     maintainers = with maintainers; [ ribose-jeffreylau ];
   };
-}
+}

flake.nix

@@ -6,7 +6,7 @@
     flake-utils.url = "github:numtide/flake-utils";
   };
 
-  outputs = { self, nixpkgs, flake-utils, sexp }:
+  outputs = { self, nixpkgs, flake-utils }:
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = nixpkgs.legacyPackages.${system};
@@ -23,4 +23,4 @@
           ];
         };
       });
-}
+}