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/croc/test-local-relay.nix

@@ -0,0 +1,19 @@
+{ stdenv, croc }:
+
+stdenv.mkDerivation {
+  name = "croc-test-local-relay";
+  meta.timeout = 300;
+  buildCommand = ''
+          HOME=$(mktemp -d)
+          # start a local relay
+          ${croc}/bin/croc relay --ports 11111,11112 &
+          # start sender in background
+          MSG="See you later, alligator!"
+          ${croc}/bin/croc --relay localhost:11111 send --code correct-horse-battery-staple --text "$MSG" &
+          # wait for things to settle
+          sleep 1
+          MSG2=$(${croc}/bin/croc --relay localhost:11111 --yes correct-horse-battery-staple)
+          # compare
+          [ "$MSG" = "$MSG2" ] && touch $out
+  '';
+}