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/tools/text/pru/default.nix

@@ -0,0 +1,24 @@
+{ lib
+, bundlerApp
+, bundlerUpdateScript
+}:
+
+bundlerApp rec {
+  pname = "pru";
+  gemdir = ./.;
+  exes = [ "pru" ];
+
+  meta = with lib; {
+    homepage = "https://github.com/grosser/pru";
+    description = "Pipeable Ruby";
+    longDescription = ''
+      pru allows to use Ruby scripts as filters, working as a convenient,
+      higher-level replacement of typical text processing tools (like sed, awk,
+      grep etc.).
+    '';
+    license = licenses.mit;
+    maintainers = with maintainers; [ AndersonTorres ];
+  };
+
+  passthru.updateScript = bundlerUpdateScript pname;
+}