--- a/conf/post-install	1970-01-01 03:00:01.000000000 +0300
+++ b/conf/post-install	2016-01-20 13:25:18.382233172 +0200
@@ -254,6 +254,8 @@
 }
 
 # Bootstrapping problem.
+meta_directory="@PACKAGE@/etc/postfix"
+command_directory="@PACKAGE@/bin"
 
 if [ -n "$command_directory" ]
 then
@@ -528,7 +530,16 @@
 	    # Skip uninstalled files.
 	    case $path in
 	    no|no/*) continue;;
+        # Skip immutable files from package, correct permissions provided by Nix.
+        @PACKAGE@/*) continue;
 	    esac
+        # Also skip symlinks following to /nix/store
+        if test -L $path; then
+            case "$(readlink $path)" in
+                @NIX_STORE@/*) continue;
+            esac
+        fi
+
 	    # Pick up the flags.
 	    case $flags in *u*) upgrade_flag=1;; *) upgrade_flag=;; esac
 	    case $flags in *c*) create_flag=1;; *) create_flag=;; esac