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/applications/version-management/rcs/default.nix

@@ -0,0 +1,41 @@
+{ lib, stdenv, fetchurl, buildPackages, diffutils, ed, lzip }:
+
+stdenv.mkDerivation rec {
+  pname = "rcs";
+  version = "5.10.1";
+
+  src = fetchurl {
+    url = "mirror://gnu/rcs/${pname}-${version}.tar.lz";
+    sha256 = "sha256-Q93+EHJKi4XiRo9kA7YABzcYbwHmDgvWL95p2EIjTMU=";
+  };
+
+  ac_cv_path_ED = "${ed}/bin/ed";
+  DIFF = "${diffutils}/bin/diff";
+  DIFF3 = "${diffutils}/bin/diff3";
+
+  disallowedReferences =
+    lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform)
+      [ buildPackages.diffutils buildPackages.ed ];
+
+  NIX_CFLAGS_COMPILE = "-std=c99";
+
+  hardeningDisable = lib.optional stdenv.cc.isClang "format";
+
+  nativeBuildInputs = [ lzip ];
+
+  meta = {
+    homepage = "https://www.gnu.org/software/rcs/";
+    description = "Revision control system";
+    longDescription =
+      '' The GNU Revision Control System (RCS) manages multiple revisions of
+         files. RCS automates the storing, retrieval, logging,
+         identification, and merging of revisions.  RCS is useful for text
+         that is revised frequently, including source code, programs,
+         documentation, graphics, papers, and form letters.
+      '';
+
+    license = lib.licenses.gpl3Plus;
+    maintainers = with lib.maintainers; [ eelco ];
+    platforms = lib.platforms.unix;
+  };
+}