* include/ruby/ruby.h,
  internal.h,
  ext/-test-/bignum/bigzero.c: Hide a Bignum definition.
  [ruby-core:42891] [Feature #6083]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44957 b2dd03c8-39d4-4d8f-98ff-823fe69b080e