Log Message:
Update to 1.2.18. From the changelog:

indexers:

* omindex:

  + Work around libmagic returning a MIME content-type of "Composite Document
    File V2 Document[...]" or "application/CDFV2-corrupt" by \ 
returning a more
    suitable filetype based on looking at the file's extension.

  + The starting URL wasn't previously URL encoded.  In 1.3.2, this will be
    fixed by URL encoding it as we do for the rest of the path, for the 1.2
    branch we only URL encode it if it contains a character <= 31 or at least
    one of '#', '%', ':' or '?'.  This avoids a one-off reindex of every
    document in the database in cases which work OK in practice.

  + When we skip a file because it exceeds the configured size limit, include
    that size limit in the message.

omega:

* Add support for setting the query expansion scheme to use.

portability:

* Don't compile in unixperm.cc - it isn't currently used, and it fails to build
  with mingw.  (fixes #635, reported by Alexis Denis)

* Fix warning when built with GCC 4.7.2 using -Os.

* Removed unused inline function, fixing compiler warning.