README.EXT.ja: fix probable typo

* README.EXT.ja (Appendix D): fix probable typo. RHASH_PTR() is
  not defined.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44377 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
eval.c: unused declaration

* eval.c (rb_vm_get_cref): remove unused declaration.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44378 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
assertions.rb: assert_throw

* lib/test/unit/assertions.rb (assert_throw): make an alias of
  assert_throws.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44379 b2dd03c8-39d4-4d8f-98ff-823fe69b080e