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/development/ocaml-modules/ocb-stubblr/pkg-config.patch

@@ -0,0 +1,25 @@
+--- a/src/ocb_stubblr.ml	1970-01-01 00:00:01.000000000 +0000
++++ b/src/ocb_stubblr.ml	2016-12-04 11:10:10.000000000 +0000
+@@ -31,20 +31,9 @@
+ 
+   (* XXX Would be nice to move pkg-config results to a build artefact. *)
+ 
+-  let opam_prefix =
+-    let cmd = "opam config var prefix" in
+-    lazy ( try run_and_read cmd with Failure _ ->
+-            error_msgf "error running opam")
+-
+-  let var = "PKG_CONFIG_PATH"
+-
+-  let path () =
+-    Lazy.force opam_prefix / "lib" / "pkgconfig" ::
+-      (try [Sys.getenv var] with Not_found -> []) |> String.concat ~sep:":"
+-
+   let run ~flags package =
+-    let cmd = strf "%s=%s pkg-config %s %s 2>/dev/null"
+-              var (path ()) package (String.concat ~sep:" " flags) in
++    let cmd = strf "pkg-config %s %s 2>/dev/null"
++              package (String.concat ~sep:" " flags) in
+     try `Res (run_and_read cmd) with Failure _ -> `Nonexistent
+ end
+