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/test/cross/default.nix

@@ -0,0 +1,113 @@
+{ pkgs, lib }:
+
+let
+
+  testedSystems = lib.filterAttrs (name: value: let
+    platform = lib.systems.elaborate value;
+  in platform.isLinux || platform.isWindows
+  ) lib.systems.examples;
+
+  getExecutable = pkgs: pkgFun: exec:
+    "${pkgFun pkgs}${exec}${pkgs.hostPlatform.extensions.executable}";
+
+  compareTest = { emulator, pkgFun, hostPkgs, crossPkgs, exec, args ? [] }: let
+    pkgName = (pkgFun hostPkgs).name;
+    args' = lib.concatStringsSep " " args;
+  in crossPkgs.runCommand "test-${pkgName}-${crossPkgs.hostPlatform.config}" {
+    nativeBuildInputs = [ pkgs.dos2unix ];
+  } ''
+    # Just in case we are using wine, get rid of that annoying extra
+    # stuff.
+    export WINEDEBUG=-all
+
+    HOME=$(pwd)
+    mkdir -p $out
+
+    # We need to remove whitespace, unfortunately
+    # Windows programs use \r but Unix programs use \n
+
+    echo Running native-built program natively
+
+    # find expected value natively
+    ${getExecutable hostPkgs pkgFun exec} ${args'} \
+      | dos2unix > $out/expected
+
+    echo Running cross-built program in emulator
+
+    # run emulator to get actual value
+    ${emulator} ${getExecutable crossPkgs pkgFun exec} ${args'} \
+      | dos2unix > $out/actual
+
+    echo Comparing results...
+
+    if [ "$(cat $out/actual)" != "$(cat $out/expected)" ]; then
+      echo "${pkgName} did not output expected value:"
+      cat $out/expected
+      echo "instead it output:"
+      cat $out/actual
+      exit 1
+    else
+      echo "${pkgName} test passed"
+      echo "both produced output:"
+      cat $out/actual
+    fi
+  '';
+
+  mapMultiPlatformTest = crossSystemFun: test: lib.mapAttrs (name: system: test rec {
+    crossPkgs = import pkgs.path {
+      localSystem = { inherit (pkgs.hostPlatform) config; };
+      crossSystem = crossSystemFun system;
+    };
+
+    emulator = crossPkgs.hostPlatform.emulator pkgs;
+
+    # Apply some transformation on windows to get dlls in the right
+    # place. Unfortunately mingw doesn’t seem to be able to do linking
+    # properly.
+    platformFun = pkg: if crossPkgs.hostPlatform.isWindows then
+      pkgs.buildEnv {
+        name = "${pkg.name}-winlinks";
+        paths = [pkg] ++ pkg.buildInputs;
+      } else pkg;
+  }) testedSystems;
+
+  tests = {
+
+    file = {platformFun, crossPkgs, emulator}: compareTest {
+      inherit emulator crossPkgs;
+      hostPkgs = pkgs;
+      exec = "/bin/file";
+      args = [
+        "${pkgs.file}/share/man/man1/file.1.gz"
+        "${pkgs.dejavu_fonts}/share/fonts/truetype/DejaVuMathTeXGyre.ttf"
+      ];
+      pkgFun = pkgs: platformFun pkgs.file;
+    };
+
+    hello = {platformFun, crossPkgs, emulator}: compareTest {
+      inherit emulator crossPkgs;
+      hostPkgs = pkgs;
+      exec = "/bin/hello";
+      pkgFun = pkgs: pkgs.hello;
+    };
+
+    pkg-config = {platformFun, crossPkgs, emulator}: crossPkgs.runCommand
+      "test-pkg-config-${crossPkgs.hostPlatform.config}"
+    {
+      depsBuildBuild = [ crossPkgs.pkgsBuildBuild.pkg-config ];
+      nativeBuildInputs = [ crossPkgs.pkgsBuildHost.pkg-config crossPkgs.buildPackages.zlib ];
+      depsBuildTarget = [ crossPkgs.pkgsBuildTarget.pkg-config ];
+      buildInputs = [ crossPkgs.zlib ];
+      NIX_DEBUG = 7;
+    } ''
+       mkdir $out
+       ${crossPkgs.pkgsBuildBuild.pkg-config.targetPrefix}pkg-config --cflags zlib > "$out/for-build"
+       ${crossPkgs.pkgsBuildHost.pkg-config.targetPrefix}pkg-config --cflags zlib > "$out/for-host"
+       ! diff "$out/for-build" "$out/for-host"
+    '';
+  };
+
+in {
+  gcc = (lib.mapAttrs (_: mapMultiPlatformTest (system: system // {useLLVM = false;})) tests);
+  llvm = (lib.mapAttrs (_: mapMultiPlatformTest (system: system // {useLLVM = true;})) tests);
+}