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/graphics/optar/default.nix

@@ -0,0 +1,35 @@
+{ lib, stdenv, fetchurl, imagemagick, libpng }:
+
+stdenv.mkDerivation {
+  pname = "optar";
+  version = "20150210";
+
+  src = fetchurl {
+    url    = "http://ronja.twibright.com/optar.tgz";
+    sha256 = "10lr31k3xfcpa6vxkbl3abph7j3gks2210489khnnzmhmfdnm1a4";
+  };
+
+  buildInputs = [ libpng ];
+
+  enableParallelBuilding = true;
+
+  postPatch = ''
+    substituteInPlace Makefile \
+      --replace /usr/local $out
+
+    substituteInPlace pgm2ps \
+      --replace 'convert ' "${lib.getBin imagemagick}/bin/convert "
+  '';
+
+  preInstall = ''
+    mkdir -p $out/bin
+  '';
+
+  meta = with lib; {
+    description = "OPTical ARchiver - it's a codec for encoding data on paper";
+    homepage = "http://ronja.twibright.com/optar/";
+    license = licenses.gpl2;
+    maintainers = with maintainers; [ peterhoeg ];
+    platforms = with platforms; linux; # possibly others, but only tested on Linux
+  };
+}