[ruby-cvs:68539] nagachika:r61358 (ruby_2_4): merge revision(s) 60182: [Backport #14009]

[nagachika at ruby-lang.org]

nagachika	2017-12-20 20:54:58 +0900 (Wed, 20 Dec 2017)

  New Revision: 61358

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=61358

  Log:
    merge revision(s) 60182: [Backport #14009]
    
    configure.ac: link Foundation framework
    
    * configure.ac (XLDFLAGS): link against Foundation framework and
      let __NSPlaceholderDictionary initialize, to get rid of crash
      after fork on macOS High Sierra.  [ruby-core:83239] [Bug #14009]

  Modified directories:
    branches/ruby_2_4/
  Modified files:
    branches/ruby_2_4/configure.in
    branches/ruby_2_4/version.h