[Nix] Some steps towards cross-compilation support

default.nix

@@ -1,10 +1,60 @@
 let
-  pkgs = import (fetchTarball {
+  nixpkgsFn = import (fetchTarball {
     url = https://github.com/NixOS/nixpkgs/archive/642499faefb17c3d36e074cf35b189f75ba43ee2.tar.gz;
     sha256 = "16j7gl3gg839fy54z5v4aap8lgf1ffih5swmfk62zskk30nwzfbi";
-  }) {};
+  });
+
+  # nixcrpkgs = import (fetchTarball {
+  #  url = https://github.com/DavidEGrayson/nixcrpkgs/archive/606e5fac74204643c8ca48dd73ce239b2f821d69.tar.gz;
+  #  sha256 = "19dn7i200xsv8s92kxymv3nd87jncmp3ki8pw77v2rxfvn8ldg34";
+  # }) {};
+
+  nixpkgs = nixpkgsFn {};
+
+  targets = {
+    windows = {
+      config = "x86_64-pc-mingw32";
+      libc = "msvcrt";
+      platform = {};
+      openssl.system = "mingw";
+    };
+
+    iphone = {
+      config = "aarch64-apple-ios";
+      # config = "aarch64-apple-darwin14";
+      sdkVer = "10.2";
+      xcodeVer = "8.2";
+      xcodePlatform = "iPhoneOS";
+      useiOSPrebuilt = true;
+      platform = {};
+    };
+
+    android = {
+      config = "armv7a-unknown-linux-androideabi";
+      sdkVer = "24";
+      ndkVer = "18b";
+      platform = nixpkgs.platforms.armv7a-android;
+      useAndroidPrebuilt = true;
+    };
+
+    raspberryPi = rec {
+      config = "armv6l-unknown-linux-gnueabihf";
+      platform = nixpkgs.platforms.raspberrypi;
+    };
+
+    raspberryPi2 = {
+      config = "armv7l-unknown-linux-gnueabihf";
+      platform = nixpkgs.platforms.armv7l-hf-multiplatform;
+    };
+  };
+
+  nimbus = pkgs: pkgs.callPackage ./nix/nimbus.nix {};
+
+  mapAttrs = nixpkgs.lib.attrsets.mapAttrs;
+  crossPackages = mapAttrs (target: conf: nixpkgsFn { crossSystem = conf; }) targets;
+  crossBulds = mapAttrs (target: packages: nimbus packages) crossPackages;
 
 in
 
-import ./nix/nimbus.nix { inherit pkgs; }
+(nimbus nixpkgs) // crossBulds
 

nix/nim.nix

@@ -1,4 +1,5 @@
-{ stdenv, lib, makeWrapper, git, nodejs, openssl, pcre, readline, sqlite }:
+{ stdenv, lib, makeWrapper, git, clang, nodejs, openssl, pcre, readline, sqlite }:
+
 let
   csources = fetchTarball {
     url = https://github.com/nim-lang/csources/archive/b56e49bbedf62db22eb26388f98262e2948b2cbc.tar.gz;
@@ -44,23 +45,23 @@ in stdenv.mkDerivation rec {
   #    used for bootstrapping, but koch insists on moving the nim compiler around
   #    as part of building it, so it cannot be read-only
 
-  buildInputs  = [
+  buildInputs = [
     makeWrapper nodejs
-    openssl pcre readline sqlite git
+    clang openssl pcre readline sqlite git
   ];
 
-  buildPhase   = ''
+  buildPhase = ''
     export HOME=$TMP
     mkdir -p dist
     cp -r ${nimble} dist/nimble
     cp -r ${csources} csources
     chmod 755 $(find csources dist/nimble -type d)
     cd csources
-    sh build.sh
+    CC="clang" LD="clang" sh build.sh
     cd ..
-    bin/nim c -d:release koch.nim
-    ./koch boot -d:release
-    ./koch tools -d:release
+    bin/nim c --cc:clang -d:release koch.nim
+    ./koch boot --cc:clang -d:release
+    ./koch tools --cc:clang -d:release
   '';
 
   installPhase = ''

nix/nimbus.nix

@@ -1,8 +1,7 @@
-{ pkgs ? import <nixpkgs> {  } }:
+{ stdenv, callPackage, sqlite, clang, rocksdb }:
 
 let
-  stdenv = pkgs.stdenv;
-  nim = pkgs.callPackage ./nim.nix {};
+  nim = callPackage ./nim.nix {};
   makeLibraryPath = stdenv.lib.makeLibraryPath;
 
 in
@@ -15,11 +14,11 @@ stdenv.mkDerivation rec {
     description = "An Ethereum 2.0 Sharding Client for Resource-Restricted Devices";
     homepage = https://github.com/status-im/nimbus;
     license = [licenses.asl20];
-    platforms = platforms.unix;
+    platforms = platforms.unix ++ platforms.windows;
   };
 
   src = ./.;
-  buildInputs = [pkgs.clang nim pkgs.rocksdb pkgs.sqlite];
+  buildInputs = [clang nim rocksdb sqlite];
   LD_LIBRARY_PATH = "${makeLibraryPath buildInputs}";
 }