* enumerator.c (enumerator_with_index_i): allow Bignum as offset, to get rid of conversion exception and integer overflow. [ruby-dev:47131] [Bug #8010] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39594 b2dd03c8-39d4-4d8f-98ff-823fe69b080e