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>

nixos/modules/installer/cd-dvd/channel.nix

@@ -0,0 +1,50 @@
+# Provide an initial copy of the NixOS channel so that the user
+# doesn't need to run "nix-channel --update" first.
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  nixpkgs = lib.cleanSource pkgs.path;
+
+  # We need a copy of the Nix expressions for Nixpkgs and NixOS on the
+  # CD.  These are installed into the "nixos" channel of the root
+  # user, as expected by nixos-rebuild/nixos-install. FIXME: merge
+  # with make-channel.nix.
+  channelSources = pkgs.runCommand "nixos-${config.system.nixos.version}"
+    { preferLocalBuild = true; }
+    ''
+      mkdir -p $out
+      cp -prd ${nixpkgs.outPath} $out/nixos
+      chmod -R u+w $out/nixos
+      if [ ! -e $out/nixos/nixpkgs ]; then
+        ln -s . $out/nixos/nixpkgs
+      fi
+      ${optionalString (config.system.nixos.revision != null) ''
+        echo -n ${config.system.nixos.revision} > $out/nixos/.git-revision
+      ''}
+      echo -n ${config.system.nixos.versionSuffix} > $out/nixos/.version-suffix
+      echo ${config.system.nixos.versionSuffix} | sed -e s/pre// > $out/nixos/svn-revision
+    '';
+
+in
+
+{
+  # Provide the NixOS/Nixpkgs sources in /etc/nixos.  This is required
+  # for nixos-install.
+  boot.postBootCommands = mkAfter
+    ''
+      if ! [ -e /var/lib/nixos/did-channel-init ]; then
+        echo "unpacking the NixOS/Nixpkgs sources..."
+        mkdir -p /nix/var/nix/profiles/per-user/root
+        ${config.nix.package.out}/bin/nix-env -p /nix/var/nix/profiles/per-user/root/channels \
+          -i ${channelSources} --quiet --option build-use-substitutes false \
+          ${optionalString config.boot.initrd.systemd.enable "--option sandbox false"} # There's an issue with pivot_root
+        mkdir -m 0700 -p /root/.nix-defexpr
+        ln -s /nix/var/nix/profiles/per-user/root/channels /root/.nix-defexpr/channels
+        mkdir -m 0755 -p /var/lib/nixos
+        touch /var/lib/nixos/did-channel-init
+      fi
+    '';
+}