Bug#653750: section 10.7 and caching a typed list which includes a file name

[Regid Ichira]

  Based on

    $ zgrep -A22 '^10.3 File names in lists' \
    > /usr/share/doc/exim4-base/spec.txt.gz | tail -4
    Putting a file name in a list has the same effect as inserting each line of the
    file as an item in the list (blank lines and comments excepted). However, there
    is one important difference: the file is read each time the list is processed,
    so if its contents vary over time, Exim's behaviour changes.

I think the following patch should be applied to section '10.7 Named list caching':

--- spec.txt    2012-01-09 00:09:38.000000000 +0200
+++ spec.txt.mod        2012-01-09 00:11:49.000000000 +0200
@@ -7108,10 +7108,10 @@ auth_advertise_hosts = !host1 : !host2

 While processing a message, Exim caches the result of checking a named list if
 it is sure that the list is the same each time. In practice, this means that
-the cache operates only if the list contains no $ characters, which guarantees
-that it will not change when it is expanded. Sometimes, however, you may have
-an expanded list that you know will be the same each time within a given
-message. For example:
+the cache operates only if the list contains no $ characters, and no file
+names, which guarantees that it will not change when it is expanded.
+Sometimes, however, you may have an expanded list that you know will be the
+same each time within a given message. For example:

 domainlist special_domains = \
            ${lookup{$sender_host_address}cdb{/some/file}}