* bignum.c (integer_unpack_single_bdigit): Use "1 + ~u" instead of
  "-u" to suppress warning (C4146) by Visual Studio.
  Reported by ko1 via IRC.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41616 b2dd03c8-39d4-4d8f-98ff-823fe69b080e