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/tools/build-managers/gn/generic.nix

@@ -0,0 +1,60 @@
+{ stdenv, lib, fetchgit, darwin, writeText
+, ninja, python3
+, ...
+}:
+
+{ rev, revNum, version, sha256 }:
+
+let
+  revShort = builtins.substring 0 7 rev;
+  lastCommitPosition = writeText "last_commit_position.h" ''
+    #ifndef OUT_LAST_COMMIT_POSITION_H_
+    #define OUT_LAST_COMMIT_POSITION_H_
+
+    #define LAST_COMMIT_POSITION_NUM ${revNum}
+    #define LAST_COMMIT_POSITION "${revNum} (${revShort})"
+
+    #endif  // OUT_LAST_COMMIT_POSITION_H_
+  '';
+
+in stdenv.mkDerivation {
+  pname = "gn-unstable";
+  inherit version;
+
+  src = fetchgit {
+    # Note: The TAR-Archives (+archive/${rev}.tar.gz) are not deterministic!
+    url = "https://gn.googlesource.com/gn";
+    inherit rev sha256;
+  };
+
+  nativeBuildInputs = [ ninja python3 ];
+  buildInputs = lib.optionals stdenv.isDarwin (with darwin; with apple_sdk.frameworks; [
+    libobjc
+    cctools
+
+    # frameworks
+    ApplicationServices
+    Foundation
+    AppKit
+  ]);
+
+  buildPhase = ''
+    python build/gen.py --no-last-commit-position
+    ln -s ${lastCommitPosition} out/last_commit_position.h
+    ninja -j $NIX_BUILD_CORES -C out gn
+  '';
+
+  installPhase = ''
+    install -vD out/gn "$out/bin/gn"
+  '';
+
+  setupHook = ./setup-hook.sh;
+
+  meta = with lib; {
+    description = "A meta-build system that generates build files for Ninja";
+    homepage = "https://gn.googlesource.com/gn";
+    license = licenses.bsd3;
+    platforms = platforms.unix;
+    maintainers = with maintainers; [ stesie matthewbauer primeos ];
+  };
+}