Add dhall-haskell submodule

We need the latest version of the Dhall interpreter, but that needs
a pin to Nixpkgs release-17.09. Use submodule rather than a fetchgit
because dhall-haskell requires a submodule itself, and fetgit does
not pull this in.

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "dhall-haskell"]
+	path = dhall-haskell
+	url = https://github.com/dhall-lang/dhall-haskell.git

default.nix

@@ -22,7 +22,7 @@ let
     rev = "3985d04b2cfe144beaf0fde58b2904763004197f";
   };
 
-in { nixpkgs ? nixpkgs' }:
+in { nixpkgs ? nixpkgs', dhall-haskell ? ./dhall-haskell.nix }:
 
 import nixpkgs {
   # Evaluate an overlayed Nixpkgs for a Genode target
@@ -32,5 +32,5 @@ import nixpkgs {
     isGenode = true;
     imports = [ ./platform.nix ];
   };
-  overlays = [ toolchainOverlay pkgOverlay ];
+  overlays = [ (toolchainOverlay dhall-haskell) pkgOverlay ];
 }

dhall-haskell

@@ -0,0 +1 @@
+Subproject commit 6a8e7e12cc95376dfd9ddfba673e7d0ae0d3b191

dhall/genode.nix

@@ -6,6 +6,6 @@
 
 fetchgit
   { url = "https://git.sr.ht/~ehmry/dhall-genode";
-    rev = "4b03fc71a4529cc35cef9dfe9d95ec431f8246e6";
-    sha256 = "0a2ff2d68yxvg2vwdbigakglixxbw063bays0mg9hkbd8570l3h3";
+    rev = "f04577c5a1eef0598cc24a04f395ff139f7c8bac";
+    sha256 = "0anszk0mgajn59hr93gbp2abkc2xp34f43vgpz9cpyglfjbzkfi0";
   }

dhall/prelude-9.0.0.nix

@@ -6,13 +6,13 @@
 
 stdenvNoCC.mkDerivation {
   name = "dhall-prelude";
-  version = "9.0.0";
+  version = " 10.0.0";
 
   src = fetchFromGitHub {
     owner = "dhall-lang";
     repo = "dhall-lang";
-    rev = "6cbf57c946e7e6576babc23a38320e53ecfa6bee";
-    sha256 = "1r06fijszyifq5b4j6libwkm06g8693m9n5c4kq61dvzrjfd2gim";
+    rev = "ef644a00e77a3c2c6c503e18e65865fd6d74fc2a";
+    sha256 = "1md16ri1l6iid2p1zg17n3ap3813v0f43vrbxc280qgxhq617sdk";
   };
 
   phases = [ "unpackPhase" "installPhase" ];

release.nix

@@ -2,7 +2,8 @@
 #
 # SPDX-License-Identifier: LicenseRef-Hippocratic-1.1
 
-{ genodepkgs ? builtins.fetchGit ./., nixpkgs ? <nixpkgs> }:
+{ genodepkgs ? builtins.fetchGit ./., nixpkgs ? <nixpkgs>
+, dhall-haskell ? ./dhall-haskell.nix }:
 
 let pkgs = import ./default.nix { inherit nixpkgs; };
 in {

toolchain-overlay/default.nix

@@ -2,6 +2,8 @@
 #
 # SPDX-License-Identifier: LicenseRef-Hippocratic-1.1
 
+dhall-haskell:
+
 self: super:
 
 let
@@ -33,6 +35,8 @@ in {
       null;
   });
 
+  inherit (import dhall-haskell) linux-dhall;
+
   genodeHeaders = self.callPackage ./headers { };
 
   inherit genodelibc;