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/editors/emacs/elisp-packages/urweb-mode/default.nix

@@ -0,0 +1,27 @@
+{ lib
+, trivialBuild
+, urweb
+, cl-lib
+, flycheck
+}:
+
+trivialBuild {
+  pname = "urweb-mode";
+
+  inherit (urweb) src version;
+
+  packageRequires = [
+    cl-lib
+    flycheck
+  ];
+
+  postUnpack = ''
+    sourceRoot=$sourceRoot/src/elisp
+  '';
+
+  meta = {
+    description = "Major mode for editing Ur/Web";
+    inherit (urweb.meta) license homepage;
+    maintainers = [ lib.maintainers.sternenseemann ];
+  };
+}