Some cleanups in the activation script:

* Moved some scriptlets to the appropriate modules.
* Put the scriptlet that sets the default path at the start, since it
  never makes sense not to have it there.  It no longer needs to be
  declared as a dependency.
* If a scriptlet has no dependencies, it can be denoted as a plain
  string (i.e., `noDepEntry' is not needed anymore).

svn path=/nixos/trunk/; revision=23762

modules/programs/bash/bash.nix

@@ -1,19 +1,21 @@
 # This module defines global configuration for the Bash shell, in
 # particular /etc/bashrc and /etc/profile.
 
-{config, pkgs, ...}:
+{ config, pkgs, ... }:
+
+with pkgs.lib;
 
 let
 
   options = {
 
-    environment.shellInit = pkgs.lib.mkOption {
+    environment.shellInit = mkOption {
         default = "";
         example = ''export PATH=/godi/bin/:$PATH'';
         description = "
           Script used to initialized user shell environments.
         ";
-        merge = pkgs.lib.mergeStringOption;
+        merge = mergeStringOption;
       };
 
   };
@@ -57,4 +59,13 @@ in
     ];
 
   system.build.binsh = pkgs.bashInteractive;
+
+  system.activationScripts.binsh = stringAfter [ "stdio" ]
+    ''
+      # Create the required /bin/sh symlink; otherwise lots of things
+      # (notably the system() function) won't work.
+      mkdir -m 0755 -p /bin
+      ln -sfn ${config.system.build.binsh}/bin/sh /bin/sh
+    '';
+  
 }