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/filesystems/mtools/default.nix

@@ -0,0 +1,27 @@
+{ lib, stdenv, fetchurl, libiconv }:
+
+stdenv.mkDerivation rec {
+  pname = "mtools";
+  version = "4.0.38";
+
+  src = fetchurl {
+    url = "mirror://gnu/mtools/${pname}-${version}.tar.bz2";
+    sha256 = "sha256-e5RIX0huffCMymiwChZKE8049MY8uGhNGIdZ7nvF5yk=";
+  };
+
+  patches = lib.optional stdenv.isDarwin ./UNUSED-darwin.patch;
+
+  # fails to find X on darwin
+  configureFlags = lib.optional stdenv.isDarwin "--without-x";
+
+  buildInputs = lib.optional stdenv.isDarwin libiconv;
+
+  doCheck = true;
+
+  meta = with lib; {
+    homepage = "https://www.gnu.org/software/mtools/";
+    description = "Utilities to access MS-DOS disks";
+    platforms = platforms.unix;
+    license = licenses.gpl3;
+  };
+}