merge revision(s) r46382,r46384,r46913: [Backport #9914]

	* io.c (rb_io_advise): AIX currently does not support a 32-bit call to
	  posix_fadvise() if _LARGE_FILES is defined. Patch by Rei Odaira.
	  [ruby-core:62968] [Bug #9914]

	* 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/branches/ruby_2_1@47139 b2dd03c8-39d4-4d8f-98ff-823fe69b080e