[Nix-dev] myEnvFun rebuilds gcc

[Sergey Mironov]

Hello. I am trying to setup an dev environment with the following
expression in ~/.nixpkgs/config.nix

    gogrEnv = pkgs.myEnvFun rec {
      name = "gogr";
      buildInputs = [
        pkgconfig
        cmake
        qt4
        gcc
        ];
    };

When I type nix-env -i env-gogr, it starts building gcc locally. At
the same time, typing nix-env -i -A nixpkgs_sys.gcc just links
prebuild gcc (4.5.1) to the current environment. Why can't system do
just the same for dev-env? Am I doing something wrong ?

Note, gcc is the only 'unlucky' package. Without it everything works
as expected - using prebuilt versions.

Thanks, Sergey