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>

nixos/modules/misc/man-db.nix

@@ -0,0 +1,73 @@
+{ config, pkgs, lib, ... }:
+
+let
+  cfg = config.documentation.man.man-db;
+in
+
+{
+  options = {
+    documentation.man.man-db = {
+      enable = lib.mkEnableOption "man-db as the default man page viewer" // {
+        default = config.documentation.man.enable;
+        defaultText = lib.literalExpression "config.documentation.man.enable";
+        example = false;
+      };
+
+      manualPages = lib.mkOption {
+        type = lib.types.path;
+        default = pkgs.buildEnv {
+          name = "man-paths";
+          paths = config.environment.systemPackages;
+          pathsToLink = [ "/share/man" ];
+          extraOutputsToInstall = [ "man" ]
+            ++ lib.optionals config.documentation.dev.enable [ "devman" ];
+          ignoreCollisions = true;
+        };
+        defaultText = lib.literalDocBook "all man pages in <option>config.environment.systemPackages</option>";
+        description = ''
+          The manual pages to generate caches for if <option>documentation.man.generateCaches</option>
+          is enabled. Must be a path to a directory with man pages under
+          <literal>/share/man</literal>; see the source for an example.
+          Advanced users can make this a content-addressed derivation to save a few rebuilds.
+        '';
+      };
+
+      package = lib.mkOption {
+        type = lib.types.package;
+        default = pkgs.man-db;
+        defaultText = lib.literalExpression "pkgs.man-db";
+        description = ''
+          The <literal>man-db</literal> derivation to use. Useful to override
+          configuration options used for the package.
+        '';
+      };
+    };
+  };
+
+  imports = [
+    (lib.mkRenamedOptionModule [ "documentation" "man" "manualPages" ] [ "documentation" "man" "man-db" "manualPages" ])
+  ];
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = [ cfg.package ];
+    environment.etc."man_db.conf".text =
+      let
+        manualCache = pkgs.runCommandLocal "man-cache" { } ''
+          echo "MANDB_MAP ${cfg.manualPages}/share/man $out" > man.conf
+          ${cfg.package}/bin/mandb -C man.conf -psc >/dev/null 2>&1
+        '';
+      in
+      ''
+        # Manual pages paths for NixOS
+        MANPATH_MAP /run/current-system/sw/bin /run/current-system/sw/share/man
+        MANPATH_MAP /run/wrappers/bin          /run/current-system/sw/share/man
+
+        ${lib.optionalString config.documentation.man.generateCaches ''
+        # Generated manual pages cache for NixOS (immutable)
+        MANDB_MAP /run/current-system/sw/share/man ${manualCache}
+        ''}
+        # Manual pages caches for NixOS
+        MANDB_MAP /run/current-system/sw/share/man /var/cache/man/nixos
+      '';
+  };
+}