Ruby

• bignum.c (power_cache_get_power): Change numdigits_ret to size_t *.
  (big2str_orig): Change len argument to size_t.
  (big2str_karatsuba): Ditto.
  (rb_big2str1): Follow the above changes.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42291 b2dd03c8-39d4-4d8f-98ff-823fe69b080e