diff --git a/pre-inst-env.in b/pre-inst-env.in
index aeadcfd820cb20c3fa0f7ee590852cee0bfcd282..1dc63cd90caaeded9a84f3dc35e9b59c0b83c1db 100644
--- a/pre-inst-env.in
+++ b/pre-inst-env.in
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 # GNU Guix --- Functional package management for GNU
-# Copyright © 2012 Ludovic Courtès <ludo@gnu.org>
+# Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
 #
 # This file is part of GNU Guix.
 #
@@ -32,6 +32,12 @@ export GUILE_LOAD_COMPILED_PATH GUILE_LOAD_PATH
 PATH="@abs_top_builddir@:$PATH"
 export PATH
 
+# Daemon helpers.
+
+NIX_ROOT_FINDER="@abs_top_builddir@/nix/scripts/list-runtime-roots"
+NIX_SETUID_HELPER="@abs_top_builddir@/nix-setuid-helper"
+export NIX_ROOT_FINDER NIX_SETUID_HELPER
+
 # The following variables need only be defined when compiling Guix
 # modules, but we define them to be on the safe side in case of
 # auto-compilation.