merge revision(s) r45793: [Backport #9608]

	* complex.c (parse_comp): replace ALLOCA_N with ALLOCV_N/ALLOCV_END
	  [Bug #9608]

	* rational.c (read_digits): ditto


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@46612 b2dd03c8-39d4-4d8f-98ff-823fe69b080e