Ruby » Ruby master

bignum.c: fix inexact estimation

• bignum.c (estimate_initial_sqrt): estimated square root is
  inexact if it is not equal to its ceil, needs Newton's method.
  [ruby-core:80696] [Bug #13440]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58366 b2dd03c8-39d4-4d8f-98ff-823fe69b080e