* numeric.c (rb_num2ull): Cast double to unsigned LONG_LONG via
  LONG_LONG instead of double to unsigned LONG_LONG directly.
  This is a challenge to fix a test_num2ull(TestNum2int)
  failure (NUM2ULL(-1.0) should be "18446744073709551615" but was "0")
  on Mac OS X with 32bit clang.
  http://a.mrkn.jp/~mrkn/chkbuild/mountain_lion/ruby-trunk-m32-o0/log/20130328T191100Z.diff.html.gz


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39991 b2dd03c8-39d4-4d8f-98ff-823fe69b080e