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/compilers/chicken/5/fetchegg/builder.sh

@@ -0,0 +1,10 @@
+source $stdenv/setup
+
+header "exporting egg ${eggName} (version $version) into $out"
+
+mkdir -p $out
+CHICKEN_EGG_CACHE=. chicken-install -r "${eggName}:${version}"
+rm ${eggName}/{STATUS,TIMESTAMP}
+cp -r ${eggName}/* $out/
+
+stopNest

pkgs/development/compilers/chicken/5/fetchegg/default.nix

@@ -0,0 +1,25 @@
+# Fetches a chicken egg from henrietta using `chicken-install -r'
+# See: http://wiki.call-cc.org/chicken-projects/egg-index-5.html
+
+{ lib, stdenvNoCC, chicken }:
+{ name, version, md5 ? "", sha256 ? "" }:
+
+if md5 != "" then
+  throw "fetchegg does not support md5 anymore, please use sha256"
+else
+stdenvNoCC.mkDerivation {
+  name = "chicken-${name}-export";
+  builder = ./builder.sh;
+  nativeBuildInputs = [ chicken ];
+
+  outputHashAlgo = "sha256";
+  outputHashMode = "recursive";
+  outputHash = sha256;
+
+  inherit version;
+
+  eggName = name;
+
+  impureEnvVars = lib.fetchers.proxyImpureEnvVars;
+}
+