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/servers/web-apps/moodle/moodle-utils.nix

@@ -0,0 +1,33 @@
+{ stdenv, unzip, ... }:
+
+let
+  buildMoodlePlugin = a@{
+    name,
+    src,
+    pluginType,
+    configurePhase ? ":",
+    buildPhase ? ":",
+    buildInputs ? [ ],
+    nativeBuildInputs ? [ ],
+    ...
+  }:
+  stdenv.mkDerivation (a // {
+    name = name;
+
+    inherit pluginType;
+    inherit configurePhase buildPhase buildInputs;
+
+    nativeBuildInputs = [ unzip ] ++ nativeBuildInputs;
+
+    installPhase = ''
+      runHook preInstall
+
+      mkdir -p "$out"
+      mv * $out/
+
+      runHook postInstall
+    '';
+  });
+in {
+  inherit buildMoodlePlugin;
+}