Log Message:
Update to 2.1.2

Changelog:
Version 2.1.2  [2018-11-19]
---------------------------

  - Bugfix: Fix crash when compiled with hardened compiler flags
    (specifically -D_GLIBCXX_ASSERTIONS)

Version 2.1.1  [2018-05-22]
---------------------------

  - Bugfix: Fix build with libunac support enabled

Version 2.1.0  [2018-04-28]
---------------------------

  - New option `--page-range` to limit search to a set of pages
  - New option `--file/-f` to read patterns from a file
  - New option `--regexp/-e` to specify multiple patterns (combined with OR).
  - New options `--files-with-matches/-l` and `--files-without-match/-L` to only
    list filenames of files that contain or don't contain matches.
  - Major manpage restructuring. It's now divided into subsections like the GNU
    grep's manpage.
  - Bugfix: Actually stop searching after first match with `-q`

Version 2.0.1  [2017-03-06]
---------------------------

  - Bugfix: Fix --cache when used with recursive search