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/networking/hans/default.nix

@@ -0,0 +1,38 @@
+{ lib, stdenv, fetchFromGitHub, nettools }:
+
+stdenv.mkDerivation rec {
+  pname = "hans";
+  version = "1.0";
+
+  src = fetchFromGitHub {
+    sha256 = "1qnfl7wr5x937b6jx3vhhvnwnrclrqvq7d7zxbfhk74pdwnjy8n4";
+    rev = "v${version}";
+    repo = "hans";
+    owner = "friedrich";
+  };
+
+  buildInputs = [ nettools ];
+
+  postPatch = ''
+    substituteInPlace src/tun.cpp --replace "/sbin/" "${nettools}/bin/"
+  '';
+
+  enableParallelBuilding = true;
+
+  installPhase = ''
+    install -D -m0755 hans $out/bin/hans
+  '';
+
+  meta = with lib; {
+    description = "Tunnel IPv4 over ICMP";
+    longDescription = ''
+      Hans makes it possible to tunnel IPv4 through ICMP echo packets, so you
+      could call it a ping tunnel. This can be useful when you find yourself in
+      the situation that your Internet access is firewalled, but pings are
+      allowed.
+    '';
+    homepage = "https://code.gerade.org/hans/";
+    license = licenses.gpl3Plus;
+    platforms = platforms.linux;
+  };
+}