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/common-updater/unstable-updater.nix

@@ -0,0 +1,112 @@
+{ lib
+, writeShellScript
+, coreutils
+, git
+, nix
+, common-updater-scripts
+}:
+
+# This is an updater for unstable packages that should always use the latest
+# commit.
+{ url ? null # The git url, if empty it will be set to src.url
+, branch ? null
+, stableVersion ? false # Use version format according to RFC 107 (i.e. LAST_TAG+date=YYYY-MM-DD)
+, tagPrefix ? "" # strip this prefix from a tag name when using stable version
+}:
+
+let
+  updateScript = writeShellScript "unstable-update-script.sh" ''
+    set -ex
+
+    url=""
+    branch=""
+    use_stable_version=""
+    tag_prefix=""
+
+    while (( $# > 0 )); do
+        flag="$1"
+        shift 1
+        case "$flag" in
+          --url=*)
+            url="''${flag#*=}"
+            ;;
+          --branch=*)
+            branch="''${flag#*=}"
+            ;;
+          --use-stable-version)
+            use_stable_version=1
+            ;;
+          --tag-prefix=*)
+            tag_prefix="''${flag#*=}"
+            ;;
+          *)
+            echo "$0: unknown option ‘''${flag}’"
+            exit 1
+            ;;
+        esac
+    done
+
+    # By default we set url to src.url
+    if [[ -z "$url" ]]; then
+        url="$(${nix}/bin/nix-instantiate $systemArg --eval -E \
+                   "with import ./. {}; $UPDATE_NIX_ATTR_PATH.src.gitRepoUrl" \
+            | tr -d '"')"
+    fi
+
+    # Get info about HEAD from a shallow git clone
+    tmpdir="$(${coreutils}/bin/mktemp -d)"
+
+    cloneArgs=(
+      --bare
+      --depth=1
+    )
+
+    if [[ -n "$branch" ]]; then
+        cloneArgs+=(--branch="$branch")
+    fi
+
+    ${git}/bin/git clone "''${cloneArgs[@]}" "$url" "$tmpdir"
+
+    pushd "$tmpdir"
+    commit_date="$(${git}/bin/git show -s --pretty='format:%cs')"
+    commit_sha="$(${git}/bin/git show -s --pretty='format:%H')"
+    if [[ -z "$use_stable_version" ]]; then
+        new_version="unstable-$commit_date"
+    else
+        depth=100
+        while (( $depth < 10000 )); do
+            last_tag="$(${git}/bin/git describe --tags --abbrev=0 2> /dev/null || true)"
+            if [[ -n "$last_tag" ]]; then
+                break
+            fi
+            ${git}/bin/git fetch --depth="$depth" --tags
+            depth=$(( $depth * 2 ))
+        done
+        if [[ -z "$last_tag" ]]; then
+            echo "Cound not found a tag within last 10000 commits" > /dev/stderr
+            exit 1
+        fi
+        if [[ -n "$tag_prefix" ]]; then
+          last_tag="''${last_tag#$tag_prefix}"
+        fi
+        new_version="$last_tag+date=$commit_date"
+    fi
+    popd
+    # ${coreutils}/bin/rm -rf "$tmpdir"
+
+    # update the nix expression
+    ${common-updater-scripts}/bin/update-source-version \
+        "$UPDATE_NIX_ATTR_PATH" \
+        "$new_version" \
+        --rev="$commit_sha"
+  '';
+
+in [
+  updateScript
+  "--url=${builtins.toString url}"
+] ++ lib.optionals (branch != null) [
+  "--branch=${branch}"
+] ++ lib.optionals stableVersion [
+  "--use-stable-version"
+  "--tag-prefix=${tagPrefix}"
+]