gistfile1.txt

let
  nixpkgsSHA = "3cb7a1cffe9bb43ec51a7707959edbebdc65ec7a"; # 2020-07-18
  pkgs = import (fetchTarball
    "https://github.com/tbenst/nixpkgs/archive/${nixpkgsSHA}.tar.gz") {
      system = builtins.currentSystem;
      overlays = [ (self: super: {
        hdf5 = super.hdf5.override { mpi = super.mpich; };
    })];
  };
in
pkgs.stdenv.mkDerivation {
    name = "circus";
    buildInputs = [
      pkgs.pythonPackages.h5py
    ];
}