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/bitcoin.nix

@@ -0,0 +1,82 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.bitcoin;
+in
+{
+  port = 9332;
+  extraOpts = {
+    rpcUser = mkOption {
+      type = types.str;
+      default = "bitcoinrpc";
+      description = ''
+        RPC user name.
+      '';
+    };
+
+    rpcPasswordFile = mkOption {
+      type = types.path;
+      description = ''
+        File containing RPC password.
+      '';
+    };
+
+    rpcScheme = mkOption {
+      type = types.enum [ "http" "https" ];
+      default = "http";
+      description = ''
+        Whether to connect to bitcoind over http or https.
+      '';
+    };
+
+    rpcHost = mkOption {
+      type = types.str;
+      default = "localhost";
+      description = ''
+        RPC host.
+      '';
+    };
+
+    rpcPort = mkOption {
+      type = types.port;
+      default = 8332;
+      description = ''
+        RPC port number.
+      '';
+    };
+
+    refreshSeconds = mkOption {
+      type = types.ints.unsigned;
+      default = 300;
+      description = ''
+        How often to ask bitcoind for metrics.
+      '';
+    };
+
+    extraEnv = mkOption {
+      type = types.attrsOf types.str;
+      default = {};
+      description = ''
+        Extra environment variables for the exporter.
+      '';
+    };
+  };
+  serviceOpts = {
+    script = ''
+      export BITCOIN_RPC_PASSWORD=$(cat ${cfg.rpcPasswordFile})
+      exec ${pkgs.prometheus-bitcoin-exporter}/bin/bitcoind-monitor.py
+    '';
+
+    environment = {
+      BITCOIN_RPC_USER = cfg.rpcUser;
+      BITCOIN_RPC_SCHEME = cfg.rpcScheme;
+      BITCOIN_RPC_HOST = cfg.rpcHost;
+      BITCOIN_RPC_PORT = toString cfg.rpcPort;
+      METRICS_ADDR = cfg.listenAddress;
+      METRICS_PORT = toString cfg.port;
+      REFRESH_SECONDS = toString cfg.refreshSeconds;
+    } // cfg.extraEnv;
+  };
+}