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/monitoring/prometheus/exporters/blackbox.nix

@@ -0,0 +1,70 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  logPrefix = "services.prometheus.exporter.blackbox";
+  cfg = config.services.prometheus.exporters.blackbox;
+
+  # This ensures that we can deal with string paths, path types and
+  # store-path strings with context.
+  coerceConfigFile = file:
+    if (builtins.isPath file) || (lib.isStorePath file) then
+      file
+    else
+      (lib.warn ''
+        ${logPrefix}: configuration file "${file}" is being copied to the nix-store.
+        If you would like to avoid that, please set enableConfigCheck to false.
+      '' /. + file);
+  checkConfigLocation = file:
+    if lib.hasPrefix "/tmp/" file then
+      throw
+      "${logPrefix}: configuration file must not reside within /tmp - it won't be visible to the systemd service."
+    else
+      true;
+  checkConfig = file:
+    pkgs.runCommand "checked-blackbox-exporter.conf" {
+      preferLocalBuild = true;
+      buildInputs = [ pkgs.buildPackages.prometheus-blackbox-exporter ];
+    } ''
+      ln -s ${coerceConfigFile file} $out
+      blackbox_exporter --config.check --config.file $out
+    '';
+in {
+  port = 9115;
+  extraOpts = {
+    configFile = mkOption {
+      type = types.path;
+      description = ''
+        Path to configuration file.
+      '';
+    };
+    enableConfigCheck = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Whether to run a correctness check for the configuration file. This depends
+        on the configuration file residing in the nix-store. Paths passed as string will
+        be copied to the store.
+      '';
+    };
+  };
+
+  serviceOpts = let
+    adjustedConfigFile = if cfg.enableConfigCheck then
+      checkConfig cfg.configFile
+    else
+      checkConfigLocation cfg.configFile;
+  in {
+    serviceConfig = {
+      AmbientCapabilities = [ "CAP_NET_RAW" ]; # for ping probes
+      ExecStart = ''
+        ${pkgs.prometheus-blackbox-exporter}/bin/blackbox_exporter \
+          --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
+          --config.file ${escapeShellArg adjustedConfigFile} \
+          ${concatStringsSep " \\\n  " cfg.extraFlags}
+      '';
+      ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
+    };
+  };
+}