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/subnetcalc/default.nix

@@ -0,0 +1,31 @@
+{ lib, stdenv, fetchFromGitHub, cmake, ninja }:
+
+stdenv.mkDerivation rec {
+  pname = "subnetcalc";
+  version = "2.4.19";
+
+  src = fetchFromGitHub {
+    owner = "dreibh";
+    repo = pname;
+    rev = "${pname}-${version}";
+    sha256 = "sha256-70OHHcdCsZBa95KQEEYhs6LfpjPg+ULOB+A+VrQVltU=";
+  };
+
+  nativeBuildInputs = [ cmake ninja ];
+
+  meta = with lib; {
+    description = "SubNetCalc is an IPv4/IPv6 subnet address calculator";
+    longDescription = ''
+      SubNetCalc is an IPv4/IPv6 subnet address calculator. For given IPv4 or
+      IPv6 address and netmask or prefix length, it calculates network address,
+      broadcast address, maximum number of hosts and host address range. Also,
+      it prints the addresses in binary format for better understandability.
+      Furthermore, it prints useful information on specific address types (e.g.
+      type, scope, interface ID, etc.).
+    '';
+    homepage = "https://www.uni-due.de/~be0001/subnetcalc/";
+    license = licenses.gpl3Plus;
+    maintainers = with maintainers; [ atila ];
+    platforms = platforms.unix;
+  };
+}