anchor.diff:    openvpn_24 = generic {
       version = "2.4.12";
       sha256 = "1vjx82nlkxrgzfiwvmmlnz8ids5m2fiqz7scy1smh3j9jnf2v5b6";
  +    extraBuildInputs = [ openssl_1_1 ];
     };
   
     openvpn = generic {
       version = "2.5.6";
       sha256 = "0gdd88rcan9vfiwkzsqn6fxxdim7kb1bsxrcra59c5xksprpwfik";
  +    extraBuildInputs = [ openssl ];
     };
   }
  
positive.code: 
          nativeBuildInputs = [ pkg-config ];
  
          buildInputs = [ lzo openssl ]
            ++ optional stdenv.isLinux pam
            ++ optional withIpRoute iproute2
            ++ optional useSystemd systemd
            ++ optional pkcs11Support pkcs11helper;
  
          configureFlags = optionals withIpRoute [
            "--enable-iproute2"
  
negative.code: , iproute2
  , lzo
  , openssl
  , openssl_1_1
  , pam
  , useSystemd ? stdenv.isLinux
  , systemd
  