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/misc/rcm/default.nix

@@ -0,0 +1,30 @@
+{ lib
+, stdenv
+, fetchurl
+}:
+
+stdenv.mkDerivation rec {
+  pname = "rcm";
+  version = "1.3.4";
+
+  src = fetchurl {
+    url = "https://thoughtbot.github.io/rcm/dist/rcm-${version}.tar.gz";
+    sha256 = "sha256-mxGuN0Sc9NI07G0TSEeb/tMlPauhH36ed0BZhltmwko=";
+  };
+
+  patches = [ ./fix-rcmlib-path.patch ];
+
+  postPatch = ''
+    for f in bin/*.in; do
+      substituteInPlace $f --subst-var-by rcm $out
+    done
+  '';
+
+  meta = with lib; {
+    homepage = "https://github.com/thoughtbot/rcm";
+    description = "Management Suite for Dotfiles";
+    license = licenses.bsd3;
+    maintainers = with maintainers; [ malyn AndersonTorres ];
+    platforms = with platforms; unix;
+  };
+}