anchor.diff:      owner = "GNS3";
       repo = pname;
       rev = "v${version}";
  -    sha256 = "0pvdqs6kjz0x0wqb5f1k3r25dg82wssm7wz4psm0m6bxsvf5l0i5";
  +    hash = "sha256-JQJa3NZ9mQqqvuTzU7XmAr1WRB4zuLIwBx18OY3GbV8=";
     };
   
     nativeBuildInputs = [ cmake ];
  
positive.code:   cmakeFlags = [ "-DDYNAMIPS_CODE=stable" ];
  
    meta = with lib; {
      description = "A Cisco router emulator";
      longDescription = ''
        Dynamips is an emulator computer program that was written to emulate Cisco
        routers.
      '';
      inherit (src.meta) homepage;
      license = licenses.gpl2Plus;
      platforms = platforms.linux;
      maintainers = with maintainers; [ primeos ];
  
negative.code: { lib
  , stdenv
  , fetchFromGitHub
  , cmake
  , libelf
  , libpcap
  }:
  
  stdenv.mkDerivation rec {
    pname = "dynamips";
  