[exim] allow_symlink

Using Exim 4.34, my local_delivery transport is

local_delivery:
  driver = appendfile
  file = ${if eq {$domain}{mailserv.ugrad.abdn.ac.uk} \
    {"/var/ugmail/${nhash_127:$local_part}/$local_part/INBOX"}\
    {"/var/mail/${nhash_127:$local_part}/$local_part/INBOX"} }
  allow_symlink = true
  delivery_date_add
  envelope_to_add
  return_path_add
  current_directory = /
  group = mail
  mode = 0660

but gave

2004-09-14 08:44:22 1C77zC-00072W-31 == u05ajs3@???
R=localuser T=local_delivery defer (-21): appendfile: file or directory
name ""/var/ugmail/63/u05ajs3/INBOX"" is not absolute


It is true that "ugmail" is a symbolic link but I was allowing this (or
thought I was).

Anyone see what the problem is?

John Linn