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/services/system/nscd.nix

@@ -0,0 +1,96 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  nssModulesPath = config.system.nssModules.path;
+  cfg = config.services.nscd;
+
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.nscd = {
+
+      enable = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Whether to enable the Name Service Cache Daemon.
+          Disabling this is strongly discouraged, as this effectively disables NSS Lookups
+          from all non-glibc NSS modules, including the ones provided by systemd.
+        '';
+      };
+
+      config = mkOption {
+        type = types.lines;
+        default = builtins.readFile ./nscd.conf;
+        description = "Configuration to use for Name Service Cache Daemon.";
+      };
+
+      package = mkOption {
+        type = types.package;
+        default = if pkgs.stdenv.hostPlatform.libc == "glibc"
+          then pkgs.stdenv.cc.libc.bin
+          else pkgs.glibc.bin;
+        defaultText = lib.literalExpression ''
+          if pkgs.stdenv.hostPlatform.libc == "glibc"
+            then pkgs.stdenv.cc.libc.bin
+            else pkgs.glibc.bin;
+        '';
+        description = "package containing the nscd binary to be used by the service";
+      };
+
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+    environment.etc."nscd.conf".text = cfg.config;
+
+    systemd.services.nscd =
+      { description = "Name Service Cache Daemon";
+
+        before = [ "nss-lookup.target" "nss-user-lookup.target" ];
+        wants = [ "nss-lookup.target" "nss-user-lookup.target" ];
+        wantedBy = [ "multi-user.target" ];
+
+        environment = { LD_LIBRARY_PATH = nssModulesPath; };
+
+        restartTriggers = [
+          config.environment.etc.hosts.source
+          config.environment.etc."nsswitch.conf".source
+          config.environment.etc."nscd.conf".source
+        ];
+
+        # We use DynamicUser because in default configurations nscd doesn't
+        # create any files that need to survive restarts. However, in some
+        # configurations, nscd needs to be started as root; it will drop
+        # privileges after all the NSS modules have read their configuration
+        # files. So prefix the ExecStart command with "!" to prevent systemd
+        # from dropping privileges early. See ExecStart in systemd.service(5).
+        serviceConfig =
+          { ExecStart = "!@${cfg.package}/bin/nscd nscd";
+            Type = "forking";
+            DynamicUser = true;
+            RuntimeDirectory = "nscd";
+            PIDFile = "/run/nscd/nscd.pid";
+            Restart = "always";
+            ExecReload =
+              [ "${cfg.package}/bin/nscd --invalidate passwd"
+                "${cfg.package}/bin/nscd --invalidate group"
+                "${cfg.package}/bin/nscd --invalidate hosts"
+              ];
+          };
+      };
+
+  };
+}