beamPackages: Add support for Mix and Erlang.mk

pkgs/development/tools/build-managers/rebar3/default.nix

@@ -1,10 +1,9 @@
 { stdenv, writeText, callPackage, fetchurl,
-  fetchHex, erlang, hermeticRebar3 ? true, rebar3-nix-bootstrap, tree, fetchFromGitHub }:
-
+  fetchHex, erlang, hermeticRebar3 ? true, rebar3-nix-bootstrap,
+  tree, fetchFromGitHub, hexRegistrySnapshot }:
 
 let
   version = "3.0.0-beta.4";
-  registrySnapshot = callPackage ./registrySnapshot.nix { };
 
   # TODO: all these below probably should go into nixpkgs.erlangModules.sources.*
   # {erlware_commons,     "0.16.0"},
@@ -89,7 +88,7 @@ stdenv.mkDerivation {
   else [];
 
   buildInputs = [ erlang tree  ];
-  propagatedBuildInputs = [ registrySnapshot rebar3-nix-bootstrap ];
+  propagatedBuildInputs = [ hexRegistrySnapshot rebar3-nix-bootstrap ];
 
   postPatch = ''
     echo postPatch

pkgs/development/tools/build-managers/rebar3/fetch-hex.nix

@@ -1,34 +0,0 @@
-{ stdenv, fetchurl }:
-
-{ pkg, version, sha256
-, meta ? {}
-}:
-
-with stdenv.lib;
-
-stdenv.mkDerivation ({
-  name = "hex-source-${pkg}-${version}";
-
-  src = fetchurl {
-    url = "https://s3.amazonaws.com/s3.hex.pm/tarballs/${pkg}-${version}.tar";
-    inherit sha256;
-  };
-
-  phases = [ "unpackPhase" "installPhase" ];
-
-  unpackCmd = ''
-    tar -xf $curSrc contents.tar.gz
-    mkdir contents
-    tar -C contents -xzf contents.tar.gz
-  '';
-
-  installPhase = ''
-    runHook preInstall
-    mkdir "$out"
-    cp -Hrt "$out" .
-    success=1
-    runHook postInstall
-  '';
-
-  inherit meta;
-})