Ruby » Ruby master

merge revision(s) 55410: [Backport #12488]

    * ext/date/date_strftime.c (date_strftime_with_tmx): reject too
      large precision to get rid of buffer overflow.
      reported by Guido Vranken <guido AT guidovranken.nl>.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@55910 b2dd03c8-39d4-4d8f-98ff-823fe69b080e