PP/04 CVE-2011-0017 - check return value of setuid/setgid. This is a
      privilege escalation vulnerability whereby the Exim run-time user
      can cause root to append content of the attacker's choosing to
      arbitrary files.

DW/22 Bugzilla 1044: CVE-2010-4345 - partial fix: restrict default behaviour
      of CONFIGURE_OWNER and CONFIGURE_GROUP options to no longer allow a
      configuration file which is writeable by the Exim user or group.

DW/23 Bugzilla 1044: CVE-2010-4345 - part two: extend checks for writeability
      of configuration files to cover files specified with the -C option if
      they are going to be used with root privileges, not just the default
      configuration file.

DW/24 Bugzilla 1044: CVE-2010-4345 - part three: remove ALT_CONFIG_ROOT_ONLY
      option (effectively making it always true).

DW/25 Add TRUSTED_CONFIG_PREFIX_FILE option to allow alternative configuration
      files to be used while preserving root privileges.

PP/27 Bugzilla 1047: change the default for system_filter_user to be the Exim
      run-time user, instead of root.

PP/28 Add WHITELIST_D_MACROS option to let some macros be overriden by the
      Exim run-time user without dropping privileges.

DW/30 Allow TRUSTED_CONFIG_PREFIX_FILE only for Exim or CONFIGURE_OWNER, not
      for other users. Others should always drop root privileges if they use
      -C on the command line, even for a whitelisted configure file.

DW/31 Turn TRUSTED_CONFIG_PREFIX_FILE into TRUSTED_CONFIG_FILE. No prefixes.