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/build-support/closure-info.nix

@@ -0,0 +1,36 @@
+# This derivation builds two files containing information about the
+# closure of 'rootPaths': $out/store-paths contains the paths in the
+# closure, and $out/registration contains a file suitable for use with
+# "nix-store --load-db" and "nix-store --register-validity
+# --hash-given".
+
+{ stdenv, buildPackages }:
+
+{ rootPaths }:
+
+assert builtins.langVersion >= 5;
+
+stdenv.mkDerivation {
+  name = "closure-info";
+
+  __structuredAttrs = true;
+
+  exportReferencesGraph.closure = rootPaths;
+
+  preferLocalBuild = true;
+
+  PATH = "${buildPackages.coreutils}/bin:${buildPackages.jq}/bin";
+
+  builder = builtins.toFile "builder"
+    ''
+      . .attrs.sh
+
+      out=''${outputs[out]}
+
+      mkdir $out
+
+      jq -r ".closure | map(.narSize) | add" < .attrs.json > $out/total-nar-size
+      jq -r '.closure | map([.path, .narHash, .narSize, "", (.references | length)] + .references) | add | map("\(.)\n") | add' < .attrs.json | head -n -1 > $out/registration
+      jq -r .closure[].path < .attrs.json > $out/store-paths
+    '';
+}