merge r46831 partially. extracted commits are as follows. [Bug #9344]
https://github.com/k-takata/Onigmo/commit/bdfc1997aa15b6baddaf9a482c6610b32504bd86

* regcomp.c: Merge Onigmo 5.14.1 25a8a69fc05ae3b56a09.
  this includes Support for Unicode 7.0 [Bug #9092].



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@47519 b2dd03c8-39d4-4d8f-98ff-823fe69b080e