Merge branch 'master' into closure-size

Beware that stdenv doesn't build. It seems something more will be needed
than just resolution of merge conflicts.

nixos/modules/programs/bash/bash.nix

@@ -56,7 +56,7 @@ in
       */
 
       shellAliases = mkOption {
-        default = config.environment.shellAliases;
+        default = config.environment.shellAliases // { which = "type -P"; };
         description = ''
           Set of aliases for bash shell. See <option>environment.shellAliases</option>
           for an option format description.

nixos/modules/programs/tmux.nix

@@ -0,0 +1,35 @@
+{ config, pkgs, lib, ... }:
+
+let
+  inherit (lib) mkOption mkEnableOption mkIf mkMerge types;
+
+  cfg = config.programs.tmux;
+
+in
+{
+  ###### interface
+
+  options = {
+    programs.tmux = {
+
+      enable = mkEnableOption "<command>tmux</command> - a <command>screen</command> replacement.";
+
+      tmuxconf = mkOption {
+        default = "";
+        description = ''
+          The contents of /etc/tmux.conf
+        '';
+        type = types.lines;
+      };
+    };
+  };
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+    environment = {
+      systemPackages = [ pkgs.tmux ];
+      etc."tmux.conf".text = cfg.tmuxconf;
+    };
+  };
+}

nixos/modules/programs/virtualbox.nix

@@ -1,8 +1,8 @@
 let
   msg = "Importing <nixpkgs/nixos/modules/programs/virtualbox.nix> is "
-      + "deprecated, please use `services.virtualboxHost.enable = true' "
+      + "deprecated, please use `virtualisation.virtualbox.host.enable = true' "
       + "instead.";
 in {
   config.warnings = [ msg ];
-  config.services.virtualboxHost.enable = true;
+  config.virtualisation.virtualbox.host.enable = true;
 }