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/kerberos/heimdal.nix

@@ -0,0 +1,68 @@
+{ pkgs, config, lib, ... } :
+
+let
+  inherit (lib) mkIf concatStringsSep concatMapStrings toList mapAttrs
+    mapAttrsToList;
+  cfg = config.services.kerberos_server;
+  kerberos = config.krb5.kerberos;
+  stateDir = "/var/heimdal";
+  aclFiles = mapAttrs
+    (name: {acl, ...}: pkgs.writeText "${name}.acl" (concatMapStrings ((
+      {principal, access, target, ...} :
+      "${principal}\t${concatStringsSep "," (toList access)}\t${target}\n"
+    )) acl)) cfg.realms;
+
+  kdcConfigs = mapAttrsToList (name: value: ''
+    database = {
+      dbname = ${stateDir}/heimdal
+      acl_file = ${value}
+    }
+  '') aclFiles;
+  kdcConfFile = pkgs.writeText "kdc.conf" ''
+    [kdc]
+    ${concatStringsSep "\n" kdcConfigs}
+  '';
+in
+
+{
+  # No documentation about correct triggers, so guessing at them.
+
+  config = mkIf (cfg.enable && kerberos == pkgs.heimdal) {
+    systemd.services.kadmind = {
+      description = "Kerberos Administration Daemon";
+      wantedBy = [ "multi-user.target" ];
+      preStart = ''
+        mkdir -m 0755 -p ${stateDir}
+      '';
+      serviceConfig.ExecStart =
+        "${kerberos}/libexec/heimdal/kadmind --config-file=/etc/heimdal-kdc/kdc.conf";
+      restartTriggers = [ kdcConfFile ];
+    };
+
+    systemd.services.kdc = {
+      description = "Key Distribution Center daemon";
+      wantedBy = [ "multi-user.target" ];
+      preStart = ''
+        mkdir -m 0755 -p ${stateDir}
+      '';
+      serviceConfig.ExecStart =
+        "${kerberos}/libexec/heimdal/kdc --config-file=/etc/heimdal-kdc/kdc.conf";
+      restartTriggers = [ kdcConfFile ];
+    };
+
+    systemd.services.kpasswdd = {
+      description = "Kerberos Password Changing daemon";
+      wantedBy = [ "multi-user.target" ];
+      preStart = ''
+        mkdir -m 0755 -p ${stateDir}
+      '';
+      serviceConfig.ExecStart = "${kerberos}/libexec/heimdal/kpasswdd";
+      restartTriggers = [ kdcConfFile ];
+    };
+
+    environment.etc = {
+      # Can be set via the --config-file option to KDC
+      "heimdal-kdc/kdc.conf".source = kdcConfFile;
+    };
+  };
+}