Log Message:
Update groonga to 4.1.1.

Release 4.1.1 - 2015-01-29
--------------------------

Improvements
^^^^^^^^^^^^

* [windows] Improved to show error message instead of
  error code. It's easy to understand.
* [experimental][windows] Supported small start file size for database file.
  In previous versions, Groonga consumed larger initial file
  size on windows in contrast to UNIX like environment.
  To enable this feature, use ``GRN_IO_VERSION=1`` environment
  variable. This feature isn't enabled by default because it is in experimental \ 
stage.
* Supported ``SUM``, ``MIN``, ``MAX``, ``AVG`` feature for drilldown.
  This feature is supported by extending newer drilldown syntax which supports label.
  Specify ``SUM``, ``MIN``, ``MAX`` or ``AVG`` for :ref:`select-drilldown-calc-types`
  and target column for :ref:`select-drilldown-calc-target`.
  The return value is calculated based on drilldown result in group.
* [experimental] Added ``--with-jemalloc`` option to use ``jemalloc`` for \ 
``malloc()/free()``.
  It'll improve performance on multi-threading usage. For example, the performance
  of :doc:`/reference/executables/groonga` or `Mroonga \ 
<http://mroonga.org/>`__ will be improved.
  Note that this feature doesn't affect to \ 
:doc:`/reference/executables/groonga-httpd` because
  groonga-httpd uses multi-process model instead of multi-threading.
* groonga-httpd: Supported long error message over 2048 bytes.
  By this change, long error message (>2048) is not truncated.
* groonga-httpd: Supported streaming dump functionality.

Fixes
^^^^^

* Fixed mismatch between error code and error message when
  ``strerror()`` is failed. There was a case that Groonga shows
  incorrect error code as syscall error.
* Fixed to show errno in error message when unknow error is occurred.
* [windows] Fixed to return proper error code.
* Fixed a bug that there is only one section for multi-column index for
  :ref:`select-match-columns`, it doesn't return correct search results.
  For example, consider the case that there is multi-column index which is
  named as ``memo_index`` for ``title`` column and ``content`` column.
  Thus, this bug occurs when ``memo_index[0]`` which means index
  for ``title`` column is specified for :ref:`select-match-columns`.
* mecab: Added workaround for ``mecab_strerror(NULL)`` on MeCab 0.993.
  Without this workaround, Groonga aborts if there is no MeCab
  dictionary. [Reported by Shuhei Tanuma]
* groonga-httpd: Fixed a bug that custom log file is ignored.
* groonga-httpd: Fixed a bug that empty dump doesn't return.

Thanks
^^^^^^

* Shuhei Tanuma