configure.in: disable posix_fadvise

* configure.in (posix_fadvise): disable use of posix_fadvise
  itself on 32-bit AIX.  [ruby-core:62968] [Bug #9914]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46384 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-06-09

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46385 b2dd03c8-39d4-4d8f-98ff-823fe69b080e