uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

pkgs/development/beam-modules/hex/default.nix

@@ -0,0 +1,57 @@
+{ lib, stdenv, fetchFromGitHub, writeText, elixir }:
+
+let
+  shell = drv: stdenv.mkDerivation {
+    name = "interactive-shell-${drv.name}";
+    buildInputs = [ drv ];
+  };
+
+  pkg = self: stdenv.mkDerivation rec {
+    pname = "hex";
+    version = "1.0.1";
+
+    src = fetchFromGitHub {
+      owner = "hexpm";
+      repo = "hex";
+      rev = "v${version}";
+      sha256 = "sha256-5g2MDbStlUrAPQCv1xWp+oPyRIOqARmlsKo/ONLTLnY=";
+    };
+
+    setupHook = writeText "setupHook.sh" ''
+       addToSearchPath ERL_LIBS "$1/lib/erlang/lib/"
+    '';
+
+    dontStrip = true;
+
+    buildInputs = [ elixir ];
+
+    buildPhase = ''
+      runHook preBuild
+      export HEX_OFFLINE=1
+      export HEX_HOME=./
+      export MIX_ENV=prod
+      mix compile
+      runHook postBuild
+    '';
+
+    installPhase = ''
+      runHook preInstall
+
+      mkdir -p $out/lib/erlang/lib
+      cp -r ./_build/prod/lib/hex $out/lib/erlang/lib/
+
+      runHook postInstall
+    '';
+
+    meta = {
+      description = "Package manager for the Erlang VM https://hex.pm";
+      license = lib.licenses.mit;
+      homepage = "https://github.com/hexpm/hex";
+      maintainers = with lib.maintainers; [ ericbmerritt ];
+    };
+
+    passthru = {
+      env = shell self;
+    };
+};
+in lib.fix pkg