* bignum.c (rb_cstr_to_inum): Use BDIGIT_DBL to collect adjacent digits.
  (BDIGIT_DBL_MAX): New macro.
  (maxpow_in_bdigit_dbl): New function.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41747 b2dd03c8-39d4-4d8f-98ff-823fe69b080e