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/convertlit/default.nix

@@ -0,0 +1,37 @@
+{lib, stdenv, fetchzip, libtommath}:
+
+stdenv.mkDerivation rec {
+  pname = "convertlit";
+  version = "1.8";
+
+  src = fetchzip {
+    url = "http://www.convertlit.com/convertlit${lib.replaceStrings ["."] [""] version}src.zip";
+    sha256 = "182nsin7qscgbw2h92m0zadh3h8q410h5cza6v486yjfvla3dxjx";
+    stripRoot = false;
+  };
+
+  buildInputs = [libtommath];
+
+  hardeningDisable = [ "format" ];
+
+  buildPhase = ''
+    cd lib
+    make
+    cd ../clit18
+    substituteInPlace Makefile \
+      --replace ../libtommath-0.30/libtommath.a -ltommath
+    make
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp clit $out/bin
+  '';
+
+  meta = {
+    homepage = "http://www.convertlit.com/";
+    description = "A tool for converting Microsoft Reader ebooks to more open formats";
+    license = lib.licenses.gpl2;
+    platforms = lib.platforms.linux;
+  };
+}