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/rcon/default.nix

@@ -0,0 +1,30 @@
+{ lib, stdenv, fetchFromGitHub, cmake, pkg-config, glib, libbsd, check, pcre }:
+
+stdenv.mkDerivation rec {
+  pname = "rcon";
+  version = "0.6";
+
+  src = fetchFromGitHub {
+    owner = "n0la";
+    repo = "rcon";
+    rev = version;
+    sha256 = "sha256-bHm6JeWmpg42VZQXikHl+BMx9zimRLBQWemTqOxyLhw=";
+  };
+
+  nativeBuildInputs = [ cmake pkg-config ];
+
+  buildInputs = [
+    glib
+    libbsd
+    check
+    pcre
+  ];
+
+  meta = with lib; {
+    homepage = "https://github.com/n0la/rcon";
+    description = "Source RCON client for command line";
+    maintainers = with maintainers; [ f4814n ];
+    platforms = with platforms; linux ++ darwin;
+    license = licenses.bsd2;
+  };
+}