Use latest iohk-nix. Remove unused patches.

nix/config.nix

@@ -1,93 +1,3 @@
 {
-  # allow building for windows
-  allowUnsupportedSystem = true;
-  # we want the 64bit wine version
-  wine.build = "wine64";
 
-  # sadly we need to patch GHC a bit.
-  packageOverrides = ps: with ps; rec {
-       # use the pre-built rocksdb.
-       # We seem to be unable to actually
-       # build rocksdb with mingw64/gcc7
-       # without producing a partial dud.
-       #
-       # Using the pre-built rocksdb, also
-       # means we do not need the gcc7 hack
-       # in our nixpkgs to allow mingw with
-       # libwinpthreads.
-       rocksdb = with ps.stdenv;
-         if hostPlatform.isWindows
-         then pkgs.callPackage ./rocksdb-prebuilt.nix { inherit (buildPackages) fetchurl unzip; }
-         else ps.rocksdb;
-
-       # on windows we have this habit of putting libraries
-       # into `bin`, wheras on unix it's usually `lib`. For
-       # this confuses nix easily. So we'll just move the
-       # .dll's from `bin` into `$out/lib`. Such that they
-       # are trivially found.
-       openssl = ps.openssl.overrideAttrs (drv: {
-         postInstall = with ps.stdenv; drv.postInstall + lib.optionalString hostPlatform.isWindows ''
-           cp $bin/bin/*.dll $out/lib/
-         '';
-       });
-       mfpr = ps.mfpr.overrideAttrs (drv: {
-         configureFlags = with ps.stdenv; (drv.configureFlags or []) ++ lib.optional hostPlatform.isWindows "--enable-static --disable-shared";
-       });
-       libmpc = ps.libmpc.overrideAttrs (drv: {
-         configureFlags = with ps.stdenv; (drv.configureFlags or []) ++ lib.optional hostPlatform.isWindows "--enable-static --disable-shared";
-       });
-
-    haskell = lib.recursiveUpdate ps.haskell {
-      compiler.ghc844 = (ps.haskell.compiler.ghc844.override {
-        ghcFlavour = if ps.stdenv.targetPlatform == ps.stdenv.hostPlatform
-                     then "perf"
-                     else "perf-cross-ncg";
-        enableShared = ps.stdenv.targetPlatform == ps.stdenv.hostPlatform;
-        enableIntegerSimple = false;
-      }).overrideAttrs (drv: {
-        dontStrip = true;
-        hardeningDisable = [ "stackprotector" "format" ];
-        patches = (drv.patches or []) ++ [
-          ./patches/ghc/move-iserv-8.4.2.patch
-          ./patches/ghc/hsc2hs-8.4.2.patch
-          ./patches/ghc/various-8.4.2.patch
-          ./patches/ghc/lowercase-8.4.2.patch
-          ./patches/ghc/cabal-exe-ext-8.4.2.patch
-          ./patches/ghc/dll-loader-8.4.2.patch
-          ./patches/ghc/outputtable-assert-8.4.2.patch
-          ./patches/ghc/0001-Stop-the-linker-panic.patch
-          ./patches/ghc/ghc-8.4.3-Cabal2201-SMP-test-fix.patch
-          ./patches/ghc/ghc-8.4.3-Cabal2201-no-hackage-tests.patch
-          ./patches/ghc/ghc-8.4.3-Cabal2201-allow-test-wrapper.patch
-          ./patches/ghc/ghc-8.4.3-Cabal2201-response-file-support.patch
-#          ./patches/ghc/ghc-8.4.4-darwin-rec-link.patch
-        ];
-        postPatch = (drv.postPath or "") + ''
-        autoreconf
-        '';
-      });
-
-      compiler.ghc863 = (ps.haskell.compiler.ghc863.override {
-        ghcFlavour = if ps.stdenv.targetPlatform == ps.stdenv.hostPlatform
-                     then "perf"
-                     else "perf-cross-ncg";
-        enableShared = ps.stdenv.targetPlatform == ps.stdenv.hostPlatform;
-        enableIntegerSimple = false;
-      }).overrideAttrs (drv: {
-        dontStrip = true;
-        hardeningDisable = [ "stackprotector" "format" ];
-        patches = (drv.patches or []) ++ [
-          ./patches/ghc/dll-loader-8.4.2.patch
-          ./patches/ghc/0001-Stop-the-linker-panic.patch
-          ./patches/ghc/ghc-8.4.3-Cabal2201-no-hackage-tests.patch
-          ./patches/ghc/ghc-8.4.3-Cabal2201-allow-test-wrapper.patch
-          ./patches/ghc/ghc-8.4.3-Cabal2201-response-file-support.patch
-#          ./patches/ghc/ghc-8.4.4-darwin-rec-link.patch
-        ];
-        postPatch = (drv.postPath or "") + ''
-        autoreconf
-        '';
-      });
-    };
-  };
 }

nix/iohk-common.nix

@@ -18,5 +18,4 @@ import (
       inherit (spec) sha256;
     }) {
       inherit system crossSystem config;
-      nixpkgsJsonOverride = ./nixpkgs-src.json;
     }

nix/iohk-nix-src.json

@@ -1,7 +1,7 @@
 {
   "url": "https://github.com/input-output-hk/iohk-nix",
-  "rev": "9dac27bd1d1db0977977e46f9ea490e818654658",
-  "date": "2019-01-18T15:15:01+01:00",
-  "sha256": "1622w9455286v8h8phi5j043iv3bk86xyy3fkzpasn2szw2707sv",
+  "rev": "cb501358f3e6dae322f23b8634e99db1e7bc23e4",
+  "date": "2019-01-21T13:05:03+01:00",
+  "sha256": "0sqm56fna05m2mjypywxj5jpsp1cq223dl1qmfjlqihl1gdarlbh",
   "fetchSubmodules": false
-}
+}