Ruby » Ruby master

bignum.c: improve estimate

• bignum.c (estimate_initial_sqrt, rb_big_isqrt): improve initial
  estimate by sqrt(). [ruby-core:79754] [Feature #13250]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57713 b2dd03c8-39d4-4d8f-98ff-823fe69b080e