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/pptp/default.nix

@@ -0,0 +1,34 @@
+{ lib, stdenv, fetchurl, perl, ppp, iproute2 }:
+
+stdenv.mkDerivation rec {
+  pname = "pptp";
+  version = "1.10.0";
+
+  src = fetchurl {
+    url = "mirror://sourceforge/pptpclient/${pname}-${version}.tar.gz";
+    sha256 = "1x2szfp96w7cag2rcvkdqbsl836ja5148zzfhaqp7kl7wjw2sjc2";
+  };
+
+  prePatch = ''
+    substituteInPlace Makefile --replace 'install -o root' 'install'
+  '';
+
+  preConfigure = ''
+    makeFlagsArray=( IP=${iproute2}/bin/ip PPPD=${ppp}/sbin/pppd \
+                     BINDIR=$out/sbin MANDIR=$out/share/man/man8 \
+                     PPPDIR=$out/etc/ppp )
+  '';
+
+  buildInputs = [ perl ];
+
+  postFixup = ''
+    patchShebangs $out
+  '';
+
+  meta = with lib; {
+    description = "PPTP client for Linux";
+    homepage = "http://pptpclient.sourceforge.net/";
+    license = licenses.gpl2;
+    platforms = platforms.linux;
+  };
+}