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/build-support/emacs/generic.nix

@@ -0,0 +1,95 @@
+# generic builder for Emacs packages
+
+{ lib, stdenv, emacs, texinfo, writeText, gcc, ... }:
+
+with lib;
+
+{ pname
+, version ? null
+
+, buildInputs ? []
+, packageRequires ? []
+
+, meta ? {}
+
+, ...
+}@args:
+
+let
+
+  defaultMeta = {
+    broken = false;
+    platforms = emacs.meta.platforms;
+  } // optionalAttrs ((args.src.meta.homepage or "") != "") {
+    homepage = args.src.meta.homepage;
+  };
+
+in
+
+stdenv.mkDerivation ({
+  name = "emacs-${pname}${optionalString (version != null) "-${version}"}";
+
+  unpackCmd = ''
+    case "$curSrc" in
+      *.el)
+        # keep original source filename without the hash
+        local filename=$(basename "$curSrc")
+        filename="''${filename:33}"
+        cp $curSrc $filename
+        chmod +w $filename
+        sourceRoot="."
+        ;;
+      *)
+        _defaultUnpack "$curSrc"
+        ;;
+    esac
+  '';
+
+  buildInputs = [emacs texinfo] ++ packageRequires ++ buildInputs;
+  propagatedBuildInputs = packageRequires;
+  propagatedUserEnvPkgs = packageRequires;
+
+  setupHook = writeText "setup-hook.sh" ''
+    source ${./emacs-funcs.sh}
+
+    if [[ ! -v emacsHookDone ]]; then
+      emacsHookDone=1
+
+      # If this is for a wrapper derivation, emacs and the dependencies are all
+      # run-time dependencies. If this is for precompiling packages into bytecode,
+      # emacs is a compile-time dependency of the package.
+      addEnvHooks "$hostOffset" addEmacsVars
+      addEnvHooks "$targetOffset" addEmacsVars
+    fi
+  '';
+
+  doCheck = false;
+
+  meta = defaultMeta // meta;
+}
+
+// lib.optionalAttrs (emacs.nativeComp or false) {
+
+  LIBRARY_PATH = "${lib.getLib stdenv.cc.libc}/lib";
+
+  nativeBuildInputs = [ gcc ];
+
+  addEmacsNativeLoadPath = true;
+
+  postInstall = ''
+    # Besides adding the output directory to the native load path, make sure
+    # the current package's elisp files are in the load path, otherwise
+    # (require 'file-b) from file-a.el in the same package will fail.
+    mkdir -p $out/share/emacs/native-lisp
+    source ${./emacs-funcs.sh}
+    addEmacsVars "$out"
+
+    find $out/share/emacs -type f -name '*.el' -print0 \
+      | xargs -0 -n 1 -I {} -P $NIX_BUILD_CORES sh -c \
+          "emacs --batch --eval '(setq large-file-warning-threshold nil)' -f batch-native-compile {} || true"
+  '';
+}
+
+// removeAttrs args [ "buildInputs" "packageRequires"
+                      "meta"
+                    ])