* bignum.c (bary_unpack_internal): Specialized unpacker implemented.
  (bary_unpack): Support INTEGER_PACK_FORCE_GENERIC_IMPLEMENTATION.
  (rb_integer_unpack): Support INTEGER_PACK_FORCE_GENERIC_IMPLEMENTATION.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41566 b2dd03c8-39d4-4d8f-98ff-823fe69b080e