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/backup/mysql-backup.nix

@@ -0,0 +1,130 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  inherit (pkgs) mariadb gzip;
+
+  cfg = config.services.mysqlBackup;
+  defaultUser = "mysqlbackup";
+
+  backupScript = ''
+    set -o pipefail
+    failed=""
+    ${concatMapStringsSep "\n" backupDatabaseScript cfg.databases}
+    if [ -n "$failed" ]; then
+      echo "Backup of database(s) failed:$failed"
+      exit 1
+    fi
+  '';
+  backupDatabaseScript = db: ''
+    dest="${cfg.location}/${db}.gz"
+    if ${mariadb}/bin/mysqldump ${if cfg.singleTransaction then "--single-transaction" else ""} ${db} | ${gzip}/bin/gzip -c > $dest.tmp; then
+      mv $dest.tmp $dest
+      echo "Backed up to $dest"
+    else
+      echo "Failed to back up to $dest"
+      rm -f $dest.tmp
+      failed="$failed ${db}"
+    fi
+  '';
+
+in
+
+{
+  options = {
+
+    services.mysqlBackup = {
+
+      enable = mkEnableOption "MySQL backups";
+
+      calendar = mkOption {
+        type = types.str;
+        default = "01:15:00";
+        description = ''
+          Configured when to run the backup service systemd unit (DayOfWeek Year-Month-Day Hour:Minute:Second).
+        '';
+      };
+
+      user = mkOption {
+        type = types.str;
+        default = defaultUser;
+        description = ''
+          User to be used to perform backup.
+        '';
+      };
+
+      databases = mkOption {
+        default = [];
+        type = types.listOf types.str;
+        description = ''
+          List of database names to dump.
+        '';
+      };
+
+      location = mkOption {
+        type = types.path;
+        default = "/var/backup/mysql";
+        description = ''
+          Location to put the gzipped MySQL database dumps.
+        '';
+      };
+
+      singleTransaction = mkOption {
+        default = false;
+        type = types.bool;
+        description = ''
+          Whether to create database dump in a single transaction
+        '';
+      };
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+    users.users = optionalAttrs (cfg.user == defaultUser) {
+      ${defaultUser} = {
+        isSystemUser = true;
+        createHome = false;
+        home = cfg.location;
+        group = "nogroup";
+      };
+    };
+
+    services.mysql.ensureUsers = [{
+      name = cfg.user;
+      ensurePermissions = with lib;
+        let
+          privs = "SELECT, SHOW VIEW, TRIGGER, LOCK TABLES";
+          grant = db: nameValuePair "${db}.*" privs;
+        in
+          listToAttrs (map grant cfg.databases);
+    }];
+
+    systemd = {
+      timers.mysql-backup = {
+        description = "Mysql backup timer";
+        wantedBy = [ "timers.target" ];
+        timerConfig = {
+          OnCalendar = cfg.calendar;
+          AccuracySec = "5m";
+          Unit = "mysql-backup.service";
+        };
+      };
+      services.mysql-backup = {
+        description = "MySQL backup service";
+        enable = true;
+        serviceConfig = {
+          Type = "oneshot";
+          User = cfg.user;
+        };
+        script = backupScript;
+      };
+      tmpfiles.rules = [
+        "d ${cfg.location} 0700 ${cfg.user} - - -"
+      ];
+    };
+  };
+
+}