merge revision(s) r48184: [Backport #10272] [Backport #10438]

	* configure.in (__builtin_setjmp): disable with gcc/clang earlier
	  than 4.3 on Mac OS X.  [ruby-core:65174] [Bug #10272]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@48274 b2dd03c8-39d4-4d8f-98ff-823fe69b080e