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/pptpd/default.nix

@@ -0,0 +1,25 @@
+{ lib, stdenv, fetchurl, ppp }:
+
+stdenv.mkDerivation rec {
+  pname   = "pptpd";
+  version = "1.4.0";
+
+  src = fetchurl {
+    url    = "mirror://sourceforge/poptop/${pname}/${pname}-${version}/${pname}-${version}.tar.gz";
+    sha256 = "1h06gyxj51ba6kbbnf6hyivwjia0i6gsmjz8kyggaany8a58pkcg";
+  };
+
+  buildInputs = [ ppp ];
+
+  postPatch = ''
+    substituteInPlace plugins/Makefile --replace "install -o root" "install"
+  '';
+
+  meta = with lib; {
+    homepage    = "http://poptop.sourceforge.net/dox/";
+    description = "The PPTP Server for Linux";
+    platforms   = platforms.linux;
+    maintainers = with maintainers; [ obadz ];
+    license = licenses.gpl2;
+  };
+}