Use MACHINE_GNU_ARCH instead of MACHINE_ARCH.

Fix build problem on NetBSD/i386.
Add `xz' command as a TOOL.
Exactly specify xz as ARCHIVE_FORMAT, require `xz' tool to build.
Then drop buildlink with xz, it is not required.

Bump PKGREVISION.
Updated devel/gettext-tools to 0.18.3.1
Oops, missing bump.
fix last entry.
Match PLIST expection for the gconf schema location
Link explicitly against libm.
Changes 2.2.7:
* Some usage of passdb checkpassword could have been exploitable by
  local users. You may need to modify your setup to keep it working.
  See http://wiki2.dovecot.org/AuthDatabase/CheckPassword#Security
+ auth: Added ability to truncate values logged by
  auth_verbose_passwords (see 10-logging.conf comment)
+ mdbox: Added "mdbox_deleted" storage, which can be used to access
  messages with refcount=0. For example: doveadm import
  mdbox_deleted:~/mdbox "" mailbox inbox subject oops
+ ssl-params: Added ssl_dh_parameters_length setting.
- master process was doing a hostname.domain lookup for each created
  process, which may have caused a lot of unnecessary DNS lookups.
- dsync: Syncing over 100 messages at once caused problems in some
  situations, causing messages to get new UIDs.
- fts-solr: Different Solr hosts for different users didn't work.
Updated mail/dovecot2 to 2.2.7